t.sushil kumar rajan
TRANSCRIPT
INDO-RUSSIAN WORKSHOP ON SELF-PROPAGATING HIGH TEMPERATURE SYNTHESIS
NOVEMBER 27-29, 2008Indian Institute of Science, BANGALORE, INDIA 560012.
Self-propagating High Temperature Synthesis (SHS) or combustion synthesis is a facile and fast method of preparing all kinds of technologically useful oxide and non-oxide materials. Today, SHS has become a very popular method of preparing advanced materials and is practiced in 65 countries around the world. India and Russia are among the top countries in terms of publications on the topic.
The year 2008 marks two decades since the first publication of the synthesis of oxide materials by Solution Combustion (SC) technique, developed at the Indian Institute of Science, Bangalore. The 40th anniversary of the Self-propagating High Temperature Synthesis process was celebrated last year at the Institute of Structural Macroinetics and Materials Science (ISMAN), Chernoglovka, Moscow Region, Russia.
The aim of the workshop is to review the state of the art of both SHS and SC and identify the areas of future research for specific applications. Eminent Scientists from premier Institutes and Laboratories from India and Russia are participating in the workshop. Lectures on several aspects of SHS products and their applications in industry are being delivered. It is hoped that the proceedings of the workshop will help in identifying areas of future research and development programs and possible collaboration between India and Russia.
The Indian Institute of Science came into existance in the year 1909, giving shape to the extraordinary vision of Jamsetji Nusserwanji Tata. The initial endowment provided by Jamsetji Tata, the munificient grant of a vast stretch of land by the Maharajah of Mysore, and the unflinching support of the Governemnt of India were instrumental in setting up the Institute. The establishment of the Institute was an important landmark in expanding traditions of scientific research in India in the twentieth century. The Institute has always been an enduring and has assiduously maintained the highest standards of academic excellence, matching the best in the world. The IISc Centenary Celebrations are
being organized to mark ‘one hundred’ illustrious years of leadrship in science, technology and innovation.
Conveners
Prof. Arun M. Umarji Prof. Vasudevan S.
Materials Research Centre Dept. of Inoganic & Physical Chemistry Indian Institute of Science, Indian Institute of Science,C.V.Raman Road C.V.Raman RoadBangalore India 560 012 Bangalore India 560 012+91-80-22932944 / 23607316 +91-80-22932661 / [email protected] [email protected]
Prof. Rogachev Alexander S.
Head of Laboratory, Institute of Structural Macrokinetics and Materials Science, Russian Academy of sciences,142432, Chernogolovka, Moscow region, Institutskaya str.8, ISMAN.+74959628034, fax +74959628025, Email: [email protected]
Invited Talks
IL-01 Solution Combustion Synthesis of Oxide MaterialsK.C. Patil
IL-02 Combustion synthesis and structure formation in the sol-gel systems.A. Rogachev
IL-03 Combustion Synthesis and Properties of Nanocrystalline Spinel OxidesP.A. Joy
IL-04 Synthesis of the electro-conducting cermet materials on the base of Zn2SnO4.Barinova Tatyana V
IL-05 Nanosezed Oxides and Oxy-Nitrides by Aerosol ProcessesSushil Kumar Rajan
IL-06 About mechanical activation influence on the structure and properties of Ni+Al and Ti+Al mixtures.Kochetov Nikolai A
IL-07 Self-propagating High-Temperature Synthesis (SHS) of Advanced High-Temperature CeramicsSuman Mishra
IL-08 Combustion synthesis: A versatile method for preparation of functional materials A.K. Tyagi
IL-09 Combustion synthesis in the reactive multilayer nano-foils.Grigoryan Amazasp E
IL-10 Kinetics of Photocatalytic Degradation of Chlorophenol, Nitrophenol, and Their MixturesM. Giridhar
IL-11 SНS processes modeling when competitive mechanisms of heat transfer in heterogeneous mediums are taken into accountKrishenik Petr M.
IL-12 Combustion derived nano metal oxides as adsorbents for water purification G.T. Chandrappa
IL-13 Stoichiometric Modeling and “Lab-to-Fab” Transition of Solution Combustion Synthesis Process Technology K.C. Adiga
IL-14 Self-propagating high temperature synthesis at microgravitySytschev A. E.
IL-15 Soft Chemistry for Nano-Materials P.Pramanik
IL-16 Self-propagating high-temperature synthesis of complex oxides: state and perspectives of development Kuznetsov Maksim V.
IL-17 Citrate-Nitrate Based Combustion Synthesis of Nano-crystalline Multi-Component Oxides for Different Applications H.S. Maiti
IL-18 Influence of heat losses on filtration combustion of gas-solid systems Grachev Vladimir V.
IL-19 Synthesis of some interesting metal oxide nano particles employing SPC reactions.A Venkatraman
IL-20 Some case studies on combustion approaches to synthesize ChalcogenidesSundar Manoharan
IL-21 Synthesis of precursor for long afterglow phosphur by combustion SynthesisU.V. Varadaraju
IL-22 Photomagnetic and magnetic hyperthermia studies of ferrite Nanoparticles synthesized through SHS processD.Bahadur
IL-23 Mixture of fuels approach for the synthesis of novel oxide powders: Utility of combustion synthesized nanosize powders in the development of corrosion and wear resistant Ni-composite coatingsS.T. Aruna
IL-24 Noble metal ionic catalysts by solution concentration methodM.S. Hegde
IL-25 The using of synchrotron radiation time-resolved X-ray diffraction experiment for kinetic investigation of SHS with millisecond time resolution.Tolochko Boris P
IL-26 Combustion synthesis of oxide materials for catalytic applications G. Ranga Rao
IL-27 Peculiar properties of the combustion process and structure formation in Ti-Ta-C system Kurbatkina Viktoria V.
IL-28 Combustion Synthesis and Characterization of Luminescent Materials-A Review.R. Gopichandran
IL-29 Nebulized Spray Pyrolysis coupled with Chemical Vapor Synthesis to produce high surface are nanoparticles with unusual propertiesRaju Addepalle Raghurama
IL-30 Rare earth Sulfide pigment by solution combustion methodArun M Umarji
IL-31 SHS of Porous Biomaterials on TiCo-alloys with HAP for the bone implantsA.E. Sytschev
Poster Presentation
PO-01 High Oxygen Storage Capacity and high rates of CO oxidation and NO reduction catalytic properties of Ce1-xSnxO2 and Ce0.78Sn0.2Pd0.02O2-d
Asha GuptaPO-02 Nano-Structure materials by sol-gel process for various industrial
applicationsAyyalasomayajula Ratna Phani
PO-03 Combustion synthesis and colour evolution studies of Praseodymium doped Ceria: Environmentally safe red pigmentBasavaraj Angadi
PO-04 Thermoluminescence Studies of Low-Temperature nthesis of Dicalcium silicateChikkahanumantharayappa
PO-05 Spectroscopic studies of Y2O3: Sm3+ nanophosphor prepared by low-temperature solution combustionJ.R. Jayaramaiah
PO-06 Synthesis of Nanosize Co0.5Zn0.5Fe2O4 by Combustion and Precursor combustion TechniqueLactina R. Gonsalves
PO-07 Anodic oxidation of AluminiumM. Mubarak Ali
PO-08 Combustion synthesis, characterization and study of magnetic properties of alkaline earth substituted lanthanum manganitesB.M. Nagabhushana
PO-09 Solution combustion synthesis and luminescence properties of swift heavy ion irradiated mullite phosphorH. Nagabhushana
PO-10 Ionoluminescence of Dy3+ doped aluminum oxideK.R. Nagabhushana
PO-11 Combustion derived MgO for the removal of adsorbable organic halides (AOX) and total organic carbon (TOC) from paper mill effluentB. Nagappa
PO-12 Production of Hydrogen via Biomass Route: Design and Fabrication of a Robust Multi-scale System for Continuous Monitoring of Syn-Gas Treatment Using Different Packed Bed ReactorsParag A. Deshpande
PO-13 Green-light emitting long-lasting phosphorescence in SrAl2O4:Eu2+, Dy3+ phosphorH. B. Prem Kumar
PO-14 Synthesis and characterization of FeZnO4 prepared through self propagating combustion RoutePrithviraj Swamy. P.M.
PO-15 Ionic Palladium catalyzed Carbon-Carbon Coupling ReactionsSanjaykumar. S.R.
PO-16 Synthesis of microcrystalline CeAlO3 by a novel solution- combustion routeSatish Shetty
PO-17 Novel catalysts synthesized by solution combustion method for water gas shift reactionSudhanshu Sharma
PO-18 Ultrasonic nebulised spray pyrolysis of aqueous combustion mixture for the deposition of ZnO thin film gas sensorsUjwala Ail
PO-19 Combustion synthesis, characterization and luminescence studies of undoped and doped mesoporous Nd2O3
B.Umesh
PO-20 Combustion Synthesis of Mn0.3Ni0.3Zn0.4Fe2O4 nano-particles using a novel fumarato-hydrazinate precursorUmesh B. Gawas
PO-21 High temperature studies on sodium cobalt oxideVenkatesan P.
PO-22 Preparation and Sensor studies on SnO2
Mahesh D. BedrePO-23 Combustion synthesis, structural characterization and thermoluminescence
studies of -rayed Mg2SiO4 nano phosphorS.C. Prashantha
IL-01
Solution Combustion Synthesis of Oxide Materials: A brief Survey
K.C. PatilDept of Inorganic & Physical ChemistryIndian Institute of Science, Bangalore – 560 012
E-mail: [email protected] , [email protected]:
The origin and development of Solution Combustion Synthesis of oxide materials is briefly reviewed. The process has been standardized to prepare several technologically important oxide materials. The important achievements during the last two decades have been: (i) Instant synthesis of simple and complex high temperature oxide materials, (ii) Tailor making oxide materials with desired structure, composition and properties, (iii) Recipe for nanocrystalline oxide materials (iv) The ease of incorporating desired impurity ions in any oxide matrix to obtain phosphors, pigments and catalysts.
Solution combustion synthesis being facile and fast is practiced by materials scientists around the world. The highlights of the practice and growth of solution combustion synthesis of oxide materials will be presented.
IL-02
Combustion synthesis and structure formation in the sol-gel systems
A.S.Rogachev, H.E.Grigoryan, D.Yu.KovalevInstitute of Structural Macrokinetics and Materials Science
Russian Academy of Sciences, Chernogolovka, RussiaEmail: [email protected]
Abstract:
The process of sol-gel combustion, also known as solution combustion, is used for synthesis of fine oxide powders. Mechanism of this process has not been studied adequately up to date. In the present work, we report new results on the experimental study of combustion behavior and flame structure. Initial water-based solutions were prepared by mixing of metal nitrate (e.g., Fe(NO3)39H2O) as oxidizer, and glycine CH2(NH2)COOH as a fuel. The solution was dried at 330 K until formation of dense gel plates with thickness about 1 mm. Reaction of combustion was initiated locally by warm nichrome wire (600 K) in air, argon or vacuum. The process was recorded with color video camera attached to long-focus microscope. Crystal structures of the initial gels and products of combustion were determined by XRD analysis.
Results have shown complex macrostructure of the combustion wave. Zone of melting propagates ahead of the combustion front. Zone of solid product formation allocates in relatively small (few mm) area, which runs along the combustion front surface. The product grows from this area in a form of friable string. Bright glowing reaction zone locates inside the string (see Figure). Depending on preparation procedure, initial gel possess amorphous or microcrystalline structure, while the combustion product is composed of nano-crystalline oxides.
This work is supported by RFBR, grant 08-03-00890.
IL-03
Combustion Synthesis and Properties of Nanocrystalline Spinel Oxides
P.A.JoyPhysical & Materials Chemistry Division
National Chemical Laboratory, Pune 411008, IndiaE-mail: [email protected]
Abstract:
Nanoparticles of spinel-type oxides offer great advantages and applications in many important areas. Decreasing the size of the particles to nanometer size will increase the surface-to-volume ratio and this will strongly influence the physical and chemical properties of these materials. Nanosized oxides are expected to give higher sintered density at relatively lower sintering temperatures, without considerable grain growth. Several methods are conventionally used for the synthesis of nanosized spinel-type oxides and especially the ferrites, in view of the potential applications of these nanosized materials in different technological areas, as well as to study the intriguing properties of the nanomaterials. Combustion synthesis using metal nitrates as the oxidizer and glycine as the fuel, known as glycine-nitrate process (GNP), is very well known for the synthesis of mixed metal oxides. It is possible to control the flame temperature during the combustion reaction by varying the glycine to nitrate ratio. We have extended this concept to synthesize nanoparticles of spinel type oxides. Some interesting results from the studies on the properties of the nanosized oxides synthesized by the glycine-nitrate method will be discussed.
IL-04
Synthesis of electroconductive cermet material based on Zn2SnO4
T.V. Barinova, I.P. Borovinskaya, V.I. Ratnikov, A.F. BelikovaInstitute of Structural Macrokinetics, Russian Academy of Sciences, Chernogoloveka,
Moscow Region, 142432 RussiaAbstract:
The paper presents the results obtained within the development of cermet material of an inert anode for aluminum industry. Coal anodes can be substituted with inert ones. It will provide a decrease in aluminum production price and its ecological purity.
In order to obtain the anode material with the preset characteristics we chose the system of Zn-Sn-Ni-O. First of all, the oxides of this system are characterized by high chemical inertness to various electrolytes and oxygen. Secondly, in this system a complex oxide with the spinel structure Zn2SnO4 can be formed. This compound is a dielectric but it is characterized by high corrosion resistance to aggressive media at high temperatures.
The aim of our work was to obtain cermet materials in the system Zn-Sn-Ni-O which by high thermal stability and corrosion resistance and the preset specific resistance, i.e. 50 Ohm m.
The cermet material was made using the green mixture of Zn+NiO+SnO2 The main phases of the obtained cermet were Zn2SnO4, ZnO, partially unreacted NiO, intermetallic Ni3Sn, and solid solution of Ni-Sn. Dense cylindrical samples were obtained; they consisted of ZnO-based dense shell and an electroconducting layer in which the metal phase was distributed in the chemically and thermally stable oxide phase based on Zn2SnO4. The specific resistance of material was 26 Ohm m. The electroconducting properties of the cermet material can be achieved during the synthesis due to the development of such structural peculiarities as elongated particles oriented perpendicularly the pressing axis and possessing metal shells. The main metal phase responsible for obtaining the material with low specific resistance is Ni-Sn solid solution. A decrease in the specific resistance was observed when Ni-Sn metal phase consisted of long filaments oriented perpendicularly the pressing axis.
IL-05
NANOSIZED OXIDES AND OXY-NITRIDES BY AEROSOL PROCESSES
T.Sushil Kumar Rajan†
Cabot Materials Research, Negeri Sembilan, Malaysia.Email: [email protected]
Abstract:The field of nanosized particles for ceramics and composites is continuing to
show growth. The primary driving force behind this growth is the fact that not only do nanosize particle precursors exhibit a plethora of properties that are different, and often considerably improved from conventional coarse grained materials, but upon sintering, produce, smaller grain size and a more uniform grain size in the dense body. The numbers of surface atoms or molecules in nano-grained materials become comparable to the number inside the particles. Numerous techniques are available for the preparation of oxide and non-oxide nanosize ceramic powders. These ultimately fall into three broad categories of phase transformations, i.e.: solid-vapour-solid, (ii) liquid-vapour-solid, and (iii) liquid-solid. Examples include the following: (Type (i)) Inert gas condensation, laser ablation, sputtering and plasma-CVD; (Type (ii)) Vapour and aerosol precursor processes such as flame synthesis and spray pyrolysis; and (Type (iii)) Aqueous and non-aqueous solution precipitation processes.
Particle production by vapour and aerosol precursor processes is attractive, because it does not involve the liquid byproducts of wet chemistry processes while the product particles can be readily separated from the gas stream without any post processing. The four main sub-categories in this are, spray pyrolysis in a tubular reactor (SP), spray pyrolysis using a vapour flame reactor (VFSP), the emulsion combustion method (ECM) and flame spray pyrolysis (FSP).
Different nanoparticles with high purity and relatively uniform particle size distribution have been made earlier using different volatile precursors in vapour flame reactors (VFSP). The variety of products is limited by the availability of a suitable precursor with a high enough vapour pressure to feed the reactor uniformly and it is often difficult to produce multi-component materials with a homogenous chemical composition.
The aerosol spray pyrolysis reactor has an advantage as each droplet serves as a discrete micro reactor as it contains the precursor in the exact stoichiometry as desired in the product.
The production of nanosize silica of high surface area (150 m2/g ; 20nm), alumina (115 m2/g ; 20nm) and sinter active, high surface area ( 60-80 m2/g) mullite (3Al2O3.2SiO2) in a liquid fed aerosol flame reactor using tetraethoxy silane and aluminium tri-iso-propoxide as precursors is discussed here.
-Si3N4 made by the imide precipitation-pyrolysis described earlier is converted to sinter-active SiAlON in a solution combustion process – a gas producing, low temperature initiated, self-propagating process. This process has been scaled up through the emulsion combustion method (ECM). Sintering properties of SiAlON are also described here.
References1. Mädler, L., Liquid fed reactors for one-step synthesis of nano-structured particles.
KONA. 22:107-120, 2004 2. Rajan, T.S.K., Studies on Oxide, nitride and oxy-nitride ceramics. PhD thesis,
Indian Institute of Science, Bangalore, 1997. 3. Stark, W.J. and Pratsinis, S.E., Aerosol flame reactors for manufacture of
nanoparticles. Powder Technol., 126: 103-108, 2002.4. Patel, K.C., Advanced ceramics: combustion synthesis and properties. Bull Mater
Sci., 16: 533-541, 1993.
IL-06
Influence of mechanical activation on the structure and properties of Ni+Al and Ti+Al SHS-mixtures.
Kochetov N. A, Rogachev A.S., Shkodich N.F.Institute of Structural Macrokinetics, Russian Academy of Sciences, Chernogolovka,
Moscow Region, 142432 RussiaEmail: [email protected]
Abstract:
Mechanical activation of the mixtures was carried out in planetary-motion grinding mill AGO-2. We tried different atmospheres (argon and air), different balls accelerations (30, 60, 90 g) and different activation times (from 10 seconds to 9 minutes). We found, that after mechanical activation of Ni+Al and Ti+Al mixtures produced composite particles, consisted from intermixed (on micro and sub-micro) layers of initial reagents (Fig 1). Amount and size of that composite particles increased with increasing balls acceleration and activation time. After mechanical activation we could initiate gasless combustion wave in the Ti-Al system without preheating (on air after 9 minutes of activation, in the argon atmosphere – from 3 and more minutes of activation), that was impossible for us without mechanical activation. In the Ni+Al system after mechanical activation in the argon atmosphere combustion velocity increased and temperature of thermal explosion beginning decreased, but after mechanical activation in the air atmosphere combustion velocity increased only after very short time of mechanical activation ( 10 seconds), and then decreased with increasing activation time, because of aluminum oxide part increasing.
In combustion products composite particles, obtained by mechanical activation, keep their identity, that allow to produce products with unusual structure (for example functional gradient material with graded pore and particle size).
This work is supported by the Russian Foundation for Basic Research, grant 08-03-91455.
Fig.1. Composite particles, obtained by mechanical activation photo. System Ni+Al.
IL-07
Self-propagating High-Temperature Synthesis (SHS) of Advanced High-Temperature Ceramics
S. K. MishraMST Division, National Metallurgical Laboratory, Jamhedpur – 831 007, India
Email: [email protected]
Keywords: High Temperature Ceramics, Self-Propagating High-Temperature Synthesis (SHS), Diborides, SHS Dynamic Compaction, Sintering and Composites
Abstract:
Over the years, the self-propagating high-temperature synthesis (SHS) has become an interesting research field to prepare a large numbers of advanced materials. Recently, the demands for high temperature advanced ceramics have further intensified the research on SHS for efficient material preparation. In this presentation, our contributions on synthesis of various advanced high temperature ceramics, the borides, carbides, oxides and their composites by SHS processes. Several advantages and disadvantages of the SHS technique for advanced high temperature (HT) materials will be highlighted. The preparation of nano-sized powders and fine-grained in-situ high temperature ceramic composites through SHS will be discussed.
IL-08
Combustion synthesis: A versatile method for preparation of functional materials
A. K. TyagiChemistry Division, Bhabha Atomic Research Centre
Mumbai - 400 085, India
Email: [email protected]:
Functional materials are potential candidates for a variety of technological applications such as Solid Oxide Fuel Cells (SOFC), optical and magnetic systems. As governed by the final application, oxide ceramics are used in the form of sintered body having the desired shape, size and microstructure. Hence, the synthesis of powder with controlled and required characteristics is of the utmost importance. The shape, size, extent of agglomeration and purity are the important parameters, which influence the powder quality. Among the available chemical routes, the combustion technique is capable of producing the nanocrystalline powders of the oxide ceramics at lower calcination temperature in a surprisingly short time. This process involves a combustion reaction between a fuel (e.g. glycine, citric acid, urea etc.) and an oxidizer (e.g. metal nitrates). Depending upon the system, the selection of a suitable fuel is a crucial step.
In our group, wide ranging materials, viz. ionic conductors for SOFC, magnetic and optical materials have been prepared by combustion route. The specific examples are ceria, doped ceria, thoria, doped thoria, Zr0.8Ce0.2O2, YSZ, doped-Y2O3 Nd3GaO6, La1-
xCaxCrO3, La1-xSrxCrO3, SrCeO3, Sr2CeO4, LaCoO3, barium polytitanates etc. The powder properties were tailored to achieve the near theoretical density sintered pellets, while retaining the ultra-fine grains. Recently, a few biferroic materials, such YCrO3 and CeCrO3 were also prepared. A number of techniques like XRD, HT-XRD, surface area analyzer, SEM, TEM, sinterability, Raman spectroscopy, dynamic light scattering, small angle x-ray/neutron scattering, dilatometer, AC Impedance analyzer etc. were used for detailed characterization of these products. The combustion process was shown to be a simple and cost effective method, which results in the phase pure, nanocrystalline powders having high surface area and better sinterability. The crucial role of process parameters, especially fuel-to-oxidant ratio, on powder characteristics was also investigated.
IL-09
Combustion synthesis in the reactive multilayer nano-foils.
H.E.Grigoryan, A.S.Rogachev, I.Yu.YagubovaInstitute of Structural Macrokinetics and Materials Science Russian Academy of Sciences
Chernogolovka, Russia,email: [email protected]
Abstract:
Gasless combustion in multilayer foils with nano-scale thickness of the layer represents a novel class of SHS processes which can be used for the production of nano-crystalline materials, foils and coatings.
But characteristics of the combustion process for the multilayer nano-foils have not been adequately studied. In this work some new experimental data concerning the propagation of the reaction front in the Ti/Al multilayer foils will be shown.
These nano-films (fig.1) were obtained by plasma-assisted sputtering technique. Thickness of the alternate layers was varied from 4 to 500 nm, and total number of the layers was varied from 20 to 5660.
a b
Figure.1 Microstructure of Init ial foilsDefinition of position of the combustion wave as a function of time for different
experimental positions shows that in all cases, the position of the front coordinate changes linearly with time. Propagation velocity increases by increasing the initial temperature and decreasing the thickness of the layer.
Distributions of local instant velocieties shows that the instant value of the combustion velocity in multilayer foils never drop down to zero, as it frequently happens
in powder mixtures. Different kinds of combustion waves were observed. It was shown for Ni/Al foils, that reaction is so fast and exothermic that it is possible to ignite and observe reaction on the multilayer nano-foils without separation from the substrate i.e. on the substrate. Temperature profiles and combustion velocity were measured.
The SHS process in the Ti/Al, Ti/3Al, Ni/Al multilayer foils shows an example of the quasi-homogeneous gasless combustion. Deviations of instant velocity probably relate to thermal factors, such as heat evolution/heat losses and do not correlate with the fine microstructure of the foil.
This work was supported by the RFBR (Grant 07-03-00753-а) and Grant of President of Russian Federation for supporting young scientists (Grant MK- 2982.2007.3)
IL-10
Kinetics of Photocatalytic Degradation of Chlorophenol, Nitrophenol,
And Their Mixtures
Giridhar MadrasChemical Engineering Department, Indian Institute of Technology, Bangalore
Email: [email protected] Abstract:
The kinetics of photocatalytic degradation of binary mixtures of chlorophenol and nitrophenol was investigated using solution combustion synthesized nano-TiO2. The degradation rates of both organics decreased in the binary mixture compared to the individual degradation rates of the organics. This was attributed to interaction between the mother compounds, interaction between the intermediates, and competition for the active reaction site on the catalyst. A modified Langmuir-Hinshelwood kinetic model was developed, and the kinetic parameters were determined from initial rate analysis for the degradation of chlorophenol and nitrophenol. The evolution of intermediates was also investigated, and a possible pathway for degradation of chlorophenol and nitrophenol was proposed.
IL-11
SНS processes modeling when competitive mechanisms of heat transfer in heterogeneous mediums are taken into account.
P.M.Krishenik, K.G.ShkadinskiiInstitute of Structural Macrokinetics and Materials Science Russian Academy of Sciences
Chernogolovka, Russia,Email: [email protected]
Abstract:
Institute of Structural Macrokinetics and Material Science Problems, Russian Academy of Sciences, Chernogolovka, Moscow Region, 142432The autowave propagation of an exothermic transformation in energetic systems is characterized by high temperatures both in the narrow reaction zone and in a rather wide part of the heating zone. To analyze wave structures in such media, it is necessary to take into account the various types of thermal interaction between the layers. The classical concepts of combustion waves is solid reaction systems have stimulated the use of the “homogeneous” approach to analyze the structural characteristics of the front in heterogeneous media. However, the complex unsteady processes of heat transfer and exothermic chemical interaction occur in the narrow combustion zone and the characterized scales of the front can correlate with the dimensions of the alternating layers of the heterogeneous medium.
We study autowave processes taking into account the competitive mechanisms of heat transfer in heterogeneous mixture– radiative and conductive. The proposed approach allows one not only to analyze the limiting combustion modes of porous structures – quasihomogeneous and relay-race – but also study the transition from one mode to the other in the case of dominant radiative heat transfer.
The structure and the dynamics of the frontal exothermal transformation in a quasihomogeneous, transitional, and relay-race regimes are studied. Average characteristics of the front and dynamics of transformation of individual elements of a “discrete” combustion wave are analyzed using the model proposed. The sufficient conditions for the guasihomogeneous and relay-race modes of combustion are determined.
To investigate the stability of the wave solutions, the procedure of the small-perturbation method was used. The freguancy of oscillation at the boundary of oscillation
stability and the critical value of Zeldovich number characterizing the boundary of the combustion front stability were determined.
The combustion wave propagation in a carbon/dust air mixture and in a heterogeneous mixture are studied, taking into account both radiatiave and conductive heat transfer. Temperatures of the particles and gas are assumed to be different and radiative heat transfer is described by a diffusion approximation. In the absence of heat losses, transition from the slow conductive combustion to the fast radiative one is explosive in nature. In such case, both the combustion wave velocity and the width of reaction zone are enhanced by 2-3 orders of magnitude.
IL-12
Combustion derived nanometal oxides as adsorbents for water purification
G. T. Chandrappa Department of Chemistry, Central College Campus, Bangalore University,
Bangalore-560001 *e-mail: [email protected]
Abstract:
Advances in nanoscale science and engineering are providing unprecedented opportunities to develop more cost effective and environmentally acceptable water/waste water purification processes. It has been demonstrated that nanocrystalline metal oxides especially MgO, CaO and ZnO have unparallel sorption properties for polar organics and other chemical species [1]. Unique morphological features (crystal shapes), pore structure, polar nature of the surfaces and high surface areas are believed to account for unusual adsorption properties. Indeed, our main objectives here are to discuss the (i) synthesis of nanocrystalline metal oxides via solution combustion process, (ii) characterization and (iii) applications as adsorbents in the purification of surface water, groundwater and industrial wastewater streams. It is well recognized that a combustion-based technique known in the literature as Self-propagating High-temperature Synthesis (SHS) is an effective energy saving method for synthesis of a variety of advanced oxide materials [2]. Combustion process has been used by the authors to synthesize metal oxide nanoparticles such as MgO, ZnO, CaO, NiO, Co3O4, Mn3O4 , Fe2O3, and CeO2 using the respective metal nitrates as oxidizers and organic fuels. These materials were characterized by PXRD, SEM/TEM and surface area measurement. MgO, ZnO and CaO are being effectively used as adsorbents for the removal of fluoride [3], arsenic species from surface/tube well water; organic pollutants/color from paper mill and pharmaceutical effluents. The effect of adsorbent dosage, stirring time, pH on the removal of water contaminants and regeneration of used adsorbent for further use will be presented during oral presentation.
Key words: Nanometal oxide particles, combustion synthesis, water purification
References
1. K.J. Klabunde et al. Chem. Eur. J. 7 (2001) 25052. K.C. Patil, S.T. Aruna and T. Mimani, Current Opinion in Solid State and
Materials Science, 6 (2002) 507 3. B. Nagappa, G.T. Chandrappa, Microporous and Mesoporous Materials, 106
(2007) 212
IL-13
SHS of Porous Biomaterials on TiCo-alloys with HAP for the bone implants
A.E. Sytschev1, O.K. Kamynina1, S.G. Vadchenko1, E.N. Balikhina, E.A. Krylova2, I.G. Plashchina2, I.I. Selezneva3, A.N. Konovalov3, A.S. Grigor’yan4, A.K. Toporkova4
1 Institute of Structural Macrokinetics and Material Science RAS, Chernogolovka, Russia2 Emanuel Institute of Biochemical Physics RAS, Moscow, Russia
3 Institute of Theoretical and Experimental Biophysics RAS, Puschino, Russia4 Central Research Institute of Stomatology and Maxillo-facial Surgery of Federal
Agency of High-Technology Medical Care, Moscow, RussiaEmail: [email protected]
Abstract:The of this study was to investigate the structure, phase composition, mechanical
properties and biocompatibility of the porous TiCo-hydroxyapatite (HAP) biomaterials by Self-propagating High Temperature Synthesis (SHS). In experiments, we investigated the effect of HAP state (crystalline, amorphous, and doped with biopolymers) on the pore structure, microstructure, strength, and biocompatibility of synthesized materials.
The materials synthesized under optimized conditions—metallic matrix with the pore surface covered with Ca-, P-, and O-containing phases—were found to have a uniform open porosity of 60%. For the first time, we synthesized a unique porous intermetallic material (from a green mixture containing HAP and biopolymers) with a developed system of pores 200–600 m in size (strength up to 115 MPa) The alloys synthesized from green mixtures doped with crystalline HAP showed some toxicity and low adhesion ability to living cells. Meanwhile, perfectly viable cells have been found to exist in the bulk of material (inside pores). Upon addition of HAP, the adhesion ability and cells spreadability were found to increase. All this facilitates the migration of cells into the bulk of porous material. Predominant growth of cells on the pore surface and low adhesion of cells to a polished surface of synthesized materials can be associated with the presence of the Ca-, P-, and O-containing phases on the pore surface. The materials synthesized from green mixtures doped with amorphous HAP and HAP containing biopolymers were found to exhibit good adhesion and cells spreading.
AcknowledgementsThis work was supported by RFBR (Grants 08-03-00215a).
IL-14
Stoichiometric Modeling and “Lab-to-Fab” Transition of Solution Combustion Synthesis Process Technology
K.C.AdigaNanoMist Systems, USA
Email: [email protected]:
An analytical model was proposed in 1981 for balancing multi-component reactant mixtures in the context of rocket propellants and high energy condensed fuel-oxidizer compositions (K.C.Adiga, Ph.D. Dissertation). Since the 1990s the major application of this analytical model has made a transition from rocket propulsion to the world of nanomaterials. Since the model easily calculates stoichiometrically balanced compositions, the scientists involved in solution combustion synthesis (SCS) found a productive use of the model for balancing reactant compositions for synthesizing nanomaterials with multi-component reactant mixtures. The method is easy to compute using Excel spreadsheets rather than going through complex chemical equilibrium computer codes such as NASA CET86, and the analytical model is robust enough to provide reliable outcomes. This presentation will re-visit the topic with emphasis on the reactants specifications, valance assignments, the limitations of the model and ways to update the calculation process to include wider applications.
Beyond reactant modeling, there is an ever-increasing demand for large-scale manufacturing capability for the production of nanomaterials via combustion methods. This presentation will highlight a new technology that takes the laboratory “batch process” of solution combustion synthesis (SCS), discovered in the 1980s, to the gas phase microfluid “continuous process” for large-scale production of nanoparticle products. In this process, the atomization of the precursor solution takes place at ambient pressure and temperature without using nozzles. Since the solution combustion process involves a self-energized system, the process does not require flame or hot-wall reactors. The exothermic reactions are controlled by the microfluid dispersion in the gas phase where exothermic reactions take place at the droplet level. The new technology provides scalable, continuous production technology for nanomaterial powders and nano-structured energetic materials, including coatings and thin films.
IL-15
Self-propagating High-temperature Synthesis under Microgravity
A. Sytschev (1), S. Vadchenko (1), V. Sanin (1), A. Rogachev (1), V. Yukhvid (1), V. Shkiro (1), N. Kochetov (1), A. Merzhanov (1) ,O. Kamynina (1), V. Levtov (2), V.
Romanov (2), M. Maksimova (3), and A. Ivanov (3)
(1) Institute of Structural Macrokinetics and Materials Science, Chernogolovka, Russia(2) Central Research Institute for Machine Building, Korolev, Russia
(3) S.P. Korolev Rocket and Space Corporation Energia, Korolev, RussiaEmail: [email protected]
Abstract:
Self-propagating high-temperature synthesis (SHS) is usually accompanied by melting of reagents and products, spreading of melt, coalescence of droplets, diffusion and convection in melted metals and nonmetals, buoyancy of solid particles and bubbles in the melt, nucleation of solid products, crystal growth, and sample deformation. Most of these processes are affected by gravity.
The experiments carried out on the ground, under conditions of elevated artificial gravity, during parabolic flight, aboard the Mir Space Station (1997-98) and International Space Station (ISS-11, ISS-13, ISS-16 Missions) demonstrated a marked effect of gravity both on the process and its products. In cooperation with the Central Research Institute for Machine Building (TsNIIMASH) and S.P. Korolev Rocket and Space Corporation Energia а special experiment installation for microgravity research on SHS aboard the International Space Station (ISS) has been designed, produced and delivered aboard ISS.
The task objectives of SHS experiments in space are as follows: comparison between the process and product parameters obtained on the ground and in space; synthesis of high-porosity materials; “contactless" SHS in space. We studied the effect of gravity on the ceramic (Ti–Al–Si–C), intermetallic (Ni–Al), thermite (NiO–Ni–Al), Ti-Ni-Al-NiO and other systems phases and structure formation. According to our results the SHS process may be used as a hopeful technology for resource utilizations not only on the earth but also in space.
The financial support of the S.P. Korolev Rocket and Space Corporation “Energia” is gratefully acknowledged.
IL-16
Soft Chemistry for Nano-Materials
Paramanik P.Nanomaterials Laboratory, Indian Institute of Technology, Khargpur-721302, INDIA
Email: [email protected] Abstract:
Co-ordination chemistry has been utilized by various branches of science and technology. This chemistry illustrates the interactions between metal ions and anions or molecules of inorganic or organic origin. The co-ordination phenomena generate extra stabilization of metal ions so that it can remain dissolved in solution even in presence of common precipitating agents.
We have utilized this concept for making following nano or nano-structured materials.
1) High-tech ceramic oxide 2) Mesoporous materials3) Nano-sized oxides for catalyst and sensor5) Oxide phosphors of various morphology
The nano-sized ceramics like SiO2.Al2O3, ZrO2, TiO2, Mullite, Codiarites, silicates, titanates etc have become important due to evolution of new classes of properties from smaller dimensionality. For multi-component-oxide systems, the pyrophoric method is successful provided the constituent metal ion is not segregating during the thermolysis of complex mixture. . We have synthesized nano-sized multicomponent mixed oxides from the mixer of their co-ordination compounds. It has produced homogenous composition and phase formation occurs at relatively lower temperature. The segregation and solubility are very common problems for metal ions like Bi, Sn, Nb, Ta, Ti... To overcome these problems, the involvement of chelating agents are very beneficial. The chelating agents like triethanolamine, diethanolamine, diethylene glycol, nitrilotriacetic acid, oxalic acid, tartaric acid are very useful.
With small modification of the process, the sizes of the ultimate powders may reach nano-sizes. Thus various nano-sized powders of titanates, zirconates, niobates, tantalates, manganate, spinels etc have been synthesized.
Same principle has been used to make various nano-structured YVO4: RE phosphors
All these reagents reduce the cost of synthesis, but the methods are definitely cheaper than alkoxide based processes.
As the co-ordianation compounds can retard the rate of formation of precipitation reaction, by controlling the reaction conditions it may generate gel which may culminate into mesoporous materials in presence of templating agents which are mostly surfactants.
Thus we have synthesized the mesoporous ZrSiO3, Zr(HPO4)2, Sn( OH )4, Nb2O5, Ta2O5, Zr( MoO4)2, Zr( WO3)2, TiO ( HPO4 ) etc. The methods have developed many efficient nano-catalyst like n-CuCr2O4 mesoporous tin compounds and efficient sensors like nano-sized Cu and Fe niobates for efficient detectiom of LPG and H2.
IL-17
Self-propagating high-temperature synthesis of complex oxides: state and perspectives of development
M.V. Kuznetsov*
Institute of Structural Macrokinetics and Materials Science Russian Academy of Sciences, p/o Chernogolovka, Moscow region 142432 Russia
e-mail: [email protected]:
SHS of complex oxide materials, as an independent and perspective direction in materials and combustion science were formed in earlier seventies. In present report the modern state and future perspectives of the problem are discussed. The biggest success in SHS of complex oxides were achieved in elaboration of pure and doped HTSC (all known yttrium, bismuth, thallium and rare-earth based compounds), all types of ferrites (including continued technologies of its producing), refractory materials, pigments, segnetoelectrics etc.
By using SHS method and chemical products market development, the most perspective direction were chosen: SOFC structures and other functional perovskite-like compounds, including alkaline and alkaline-earth substituted LnMO3 compounds; components of rechargeable lithium batteries and its analogs; synthesis of functional ceramics (including magnetic materials synthesis under external physico-chemical affects); useful chemical products producing by using natural ore resources, industrial wastes and dumps; radioactive and high-active wastes (RAW and HAW) neutralization.
Complex investigation of heterogeneous combustion and phase formation processes requires principally new methods of analysis which are completely different from the standard optical pyrometry with its high experimental errors and micro-thermocouples methods due to its low thermal inertia. The new experimental methods for investigations of phase formation during SHS has been established. The first experiments using of penetrating synchrotron radiation and energy dispersive detectors for the different classes of complex inorganic materials was carried out in ESRF (Grenoble, France) and Daresbury (UK). A new and very sensitive thermal imaging method (Thermal Imaging Technique (TIT)) is based on the continuous registration of the whole combustion process by using a highly-sensitive IR-camera and software developed by MIKRON Instrument Co. (USA) was also used for precise registration of the combustion parameters. SHS were performed on different types of pure and doped complex inorganic
materials in pellet and powder form in a range of magnetic field strengths up to 20 T and dc electric field up to ±220 kV/m. Constant magnetic field was applied during the reaction, supplied either by a permanent magnet (1.1 T) or by an electromagnet (up to 20 T) and dc electric field were applied to along a direction of the combustion wave front propagation. The combine process of SHS and Selective Laser Sintering (SLS) of 3D articles for the different powdered compositions was realized with the optimal parameters of a laser influence, under which the SHS reaction carries under control regime.
IL-18
Citrate-Nitrate Based Combustion Synthesis of Nano-crystalline Multi-Component Oxides for Different Applications
H.S. MaitiCentral Glass & Ceramic Research Institute, CSIR, Kolkata-700032, India
Email: [email protected]:
Self-propagating anionic oxidation-reduction reactions with extra-ordinary exothermicity has been one of the convenient ways to synthesize nano-sized multi-component ceramic oxides with exotic properties. While metal nitrates in the solution form has been the most commonly used oxidizing precursor, different types of anionic reducing agents have been used by different research groups around the world. Auto-combustion of citrate-nitrate gel has been one of the routes the author’s laboratory has been pursuing to synthesize a variety of multi-component ceramic oxides for the last more than one decade. Nano-crystalline, single phase and highly homogeneous multi-component ceramic oxide powders have been prepared by this technique. Initially the reaction was conducted in glass beakers to produce a few grams of the powders. Later, the process has been scaled-up to kilogram level and made semi-continuous with the help of a spray pyrolyser designed and fabricated in house. Spray pyrolysis consists of five main steps: (i) generation of a spray from a liquid precursor by a droplet generator (ii) transport by a carrier gas flow during which solvent evaporation occurs with concomitant solute precipitation within the atomized droplets (iii) thermolysis of the precipitated particles (iv) intra-particulate sintering to form dense particles and (v) finally, extraction of the particles from the gas flow. While citric acid has been used as the most common reducing agents other chemicals e.g., L-alanine, glycene, ammonium dichromate or mixed fuels have been used for certain oxides with great advantages.
A wide variety of materials have been synthesized successfully by this technique e.g. High Tc superconducting compounds, pure and doped lanthanum manganite, doped lanthanum ferrite, doped ceria, doped lanthanum molybdate and doped lanthanum chromite etc. and they are characterized for the application as the materials for the solid oxide fuel cell and also doped lithium manganite and doped lithium cobaltite materials as applicable for the cathode materials in Li-ion rechargeable batteries. All these compounds have been successfully synthesized and fully characterized keeping in view the various applications as mentioned above. The process parameters for the synthesis of many of
these compounds in a relatively large scale by the spray pyrolysis technique have also been optimized.
Selected Bibliography:
1. J. Mater. Res., Vol. 19, No. 11, Nov 2004, DOI : 10.1557/JMR.2004.0442 S. Basu, P. Sujatha Devi and H.S. Maiti “Synthesis and properties of nanocrystalline ceria powders”
2. Applied Physics Letters Vol. 85, No.16, Oct 2004, DOI: 10.1063/1.1808505 S. Basu, P. Sujatha Devi and H.S. Maiti “A potential low-temperature oxide-ion conductor: La2−xBaxMo2O9”
3. J. Am. Ceram. Soc. 88 [4] 971–973 (2005) DOI: 10.1111/j.1551-2916.2005.00152.x: A. Kumar, P. Sujatha Devi, A Das Sharma and H.S. Maiti “A Novel Spray-Pyrolysis Technique to Produce Nanocrystalline Lanthanum Strontium Manganite Powder”
4. Electrochemical & Solid State Letters, Vol. 9 [11] (2006) A516-19.Saswati Ghosh, A. Das Sharma, R.N. Basu and H.S. Maiti, “Synthesis of La0.7Ca0.3CrO3
Using a Chromium Source”5. Mater. Res. Bull. 2007, 42, 1499-1506.Raja, M.W., Mahanty, S., Ghosh, P., Basu,
R.N. and Maiti, H.S., “Alanine-assisted low-temperature combustion synthesis of nanocrystalline LiMn2O4 for lithium-ion batteries”
6. ECS Transaction, 7 (1) 1129-1138 (2007), The Electrochemical Society. P. Pal, M.W. Raja, J. Mukhopadhyay, A. Dutta, S. Mahanty, R.N. Basu and H.S. Maiti, “Alanine Assisted Low-Temperature Synthesis and Characterization of Nanocrystalline SOFC Cathodes”
7. J. Mat. Res., Vol. 22 (2007) 1162-67. Paromita Ghosh, S. Mahanty, W. Raja, R.N. Basu and H.S. Maiti, “Structure and Optical Absorption of Combustion Synthesized Nanocrystalline LiCoO2”
8. A. Kumar, P.Sujatha Devi, A Das Sharma, J. Mukhopadhyay and H.S. Maiti, “ A process for the continuous production of sinteractive lanthanum chromite based oxides” Indian patent – 1214/DEL/04
IL-19
Influence of heat losses on filtration combustion of gas-solid systems
Vladimir V. GrachevInstitute of Structural Macrokinetics and Materials Science,
Russian Academy of Sciences, Chernogolovka, Moscow, 142432 RussiaEmail: [email protected]
Abstract:
Filtration combustion is widely applied in processes of self-propagating high-temperature synthesis. In this case an exothermic reaction takes place in porous medium between the solid reagent and gaseous oxidant which is consumed and a solid product is formed. The gas consumption in the reaction front causes a pressure gradient which drives natural filtration of oxidant through a porous substance towards the reaction front. The process of oxidant filtration plays the important role in mechanism of gas-solid combustion. In actual practice the combustion is always affected by heat losses in an environment. It is well known from the general theory of combustion there is a limit of the combustion wave propagation due to the heat losses effect. With regards to the theory of the filtration combustion of SHS-systems the heat losses effect was analyzed only for case, when all sample boundaries are closed to the gas penetration except one, which is open to exchange with a large bath of gas so that the pressure is that of the bath at that end. The reaction is initiated at the opposite end of the sample. It was shown that two modes are possible, with complete and incomplete conversion. In frames of one-dimensional model the criterion r which defines the combustion mode was derived. The limit of the combustion in the complete conversion mode exists according to the general combustion theory, but there is not the combustion limit in the incomplete conversion mode. In that theoretical analysis the initial gas content in pores was not taken into account (this assumption simplified solution of the problem).
The aim of the present work is to consider the problem in frames of the model with heat losses through the side surface and with account of the initial gas content in the sample pores. If the sample length much more than the characteristic scale of the filtration zone, the combustion wave propagation at the initial sample part (far from the open end of the sample) is only possible due to the gas in pores. In this case, the approximate analysis of the steady modes with heat losses shows that the combustion limit exists for both modes, with complete and incomplete conversion. For quasi-steady
combustion modes, when the gas flow through the open sample end into the reaction zone is essential, the presence/absence of combustion limit in the incomplete conversion mode depends on the magnitude of the criterion r. For r ~ 1, a decrease of the combustion wave velocity due to the heat losses brings to the growth in the conversion degree and the complete conversion can be achieved without extinction of the combustion. For r >> 1, the limit is reached at which the wave with incomplete conversion will not self-propagate and the combustion is extinguished.
This work was supported by the Scientific Council at the President of Russia (grant NSh-5258.2008.3), Russian Academy of Sciences (program no. 8), and Joint French–Russian Program of Scientific Cooperation (grant PICS 3462–RFBR 06-03-22000).
IL-20
Synthesis of some interesting metal oxide nano particles employing SPC reactions
A.Venkataramana,Materials Chemistry Laboratory, Department of Materials Science,
Gulbarga University, GULBARAG-585 106Email: [email protected]
Abstract:
Syntheses of metal oxide nano particles with tailored made morphologies has in recent times generated interested amongst Materials Chemists because of the challenges addressed by the normal wet chemical routes over the sophisticated physical techniques. Amongst the several wet chemical processes in the syntheses of materials, self propagating combustion (SPC) reactions have been considered as earliest. However, with the requirement of tailored made morphologies as a prerequisite for advanced materials and nanomaterials, the SPC routes have also undergone changes from high temperature to the low temperature combustion reactions, with the choice of employing different reactants, fuels, and processing conditions. Further understanding of the reaction path way/s, for such reactions, is a crucial step which requires greater attention, when reactions are carried out in solution medium, employing aqueous/non aqueous solvents.
In this talk, I will mainly deal with the synthesis of metal oxide ultrafine and nano particles through novel chemical approach such as self propagating combustion (SPC) reactions, microwave mediated combustion synthesis and solvothermal and hydrothermal approach. Easy and economic scale up of the synthesis to achieve chemical homogeneity, tailor made morphology, and possible application of the synthesised compounds will be discussed in detail.
IL-21
Some case studies on combustion approaches to synthesize chalcogenides
S. Sundar ManoharanDepartment of Chemistry and Advanced Center for Material Science,
Indian Institute of Technology Kanpur 208016 IndiaEmail: [email protected]
Abstract:Extending wet route combustion synthesis to synthesize chalcogenides requires
hybrid approaches. Bulk sintered Ag2+xSe samples were prepared employing a commercial microwave oven with 900 W, and 2.45 GHz frequency. Stoichiometric amounts of spectroscopic grade Ag(99.9%) and Se (99.9%) purity intimately mixed and compacted into cylindrical rods of 10mm x 3mm dimension and was evacuated in a quartz tube. The sealed quartz ampoules were exposed to microwave radiation at high power level for up to 10 min. During the exposure bright flashes were observed due to excitation and de-excitation of elemental Se. As a result an in situ exothermic reaction occurs which instantly leads to product formation. Further, due to volumetric heating throughout the sample, in situ sintering occurs simultaneously. This process distinguishes itself as a unique approach compared to other chemical routes.
Figure shows compositional analysis and magneto resistive ratio plot as a function of Ag, the EPMA mapping of Selenium in Ag2Se sintered samples and
the resistance versus temperature plot of the silver selenide samples.
IL-22
Synthesis of precursor for long afterglow phosphur by combustion synthesis
Varadaraju U.V.Material Science Research Centre, Indian Institute of Technology, Madras, Chennai-
600036Email: [email protected]
IL-23
Photomagnetic and magnetic hyperthermia studies of ferrite Nanoparticles synthesized through SHS process
D.Bahadur and S.Rajakumar Dept of Metallurgical Engineering and Materials Science,Indian Institute of Technology Bombay, Mumbai-400076.
Email: [email protected]:
We present synthesis of the strontium ferrite, barium ferrite and Co substituted nickel zinc ferrite and substituted iron oxide nano particles through gel-combustion technique. We have investigated the influence of the synthesis parameters like nitrate to fuel ratio and pH. Citric acid has been used as a fuel in all cases. The strontium ferrite nano particles prepared with nitrate to fuel ratio 1:1 with pH 7 shows different shapes like rods, bipod and tripod. With the addition of 4% PVP gives reduction in size and also the cubic shapes forms instead of rods. The anisotropic shape formation was explained based on selected growth along <100> directions which are kinetically controlled growth at low temperature synthesis. The addition of PVP (poly vinyl pyrollidone) to the starting solution acts as a passivating agents and slow down the growth rate along <100> and allows them to grow along <111> direction which causes the formation of cubic shapes. The photo induced magnetic properties of Co substituted nickel zinc ferrite, shows a 12% increase in magnetization with the application light. The PIM (photo induced magnetic) properties will be discussed.
We will also present some of our recent studies on the magnetic hyperthermia treatment of cancer using suspension of such ferrite nano particles.
IL-24
Mixture of fuels approach for the synthesis of novel oxide powders: Utility of combustion synthesized nanosize powders in the development
of corrosion and wear resistant Ni-composite coatingsS.T. Aruna
Surface Engineering Division, National Aerospace Laboratories,Post Bag No. 1779, Bangalore – 560 017, INDIA
E-mail:[email protected]:
A large number of technologically important nanosize oxide powders have been prepared using solution combustion process and were used in the development of corrosion and wear resistant electrocomposite coatings. The concept of mixture of fuels approach was demonstrated for the first time for the solution combustion synthesis of nanosize zirconia toughened alumina (ZTA). It was found that the mixture of fuels not only helped in decreasing the particle size but also facilitated in lowering the sintering temperature of the powders. In a recent work, during the preparation of nanocomposites of CeO2-Al2O3 using mixture of fuels, in addition to the lowering of particle size and low sintering temperature of the product, the possibility of stabilizing lower oxidation state oxides like CeAlO3 was observed. The work on the stabilization of CeAlO3 using mixture of fuels approach will be briefly presented.
Nanosize oxides like alumina, ceria, zirconia, zirconia toughened alumina, alumina yttria stabilized zirconia (AZY), yttria doped ceria synthesized by solution combustion method have been incorporated in the electrodeposited Ni coating. The microhardness, corrosion and wear resistance properties of Ni-composite coatings have been studied in detail. The properties can be tailored by suitable selection of the particles and electroplating conditions.
IL-25
Noble metal ionic catalysts synthesized by solution concentration method
M.S. Hegde Solid State and Structural Chemistry Unit
Indian Institute of Science Bangalore Email: [email protected]
Abstract:
With increasing stringent regulation and legislation on auto exhaust emission, the present focus is to develop new, efficient exhaust catalysts. The major pollutants in exhausts are CO, NOx and unburnt hydrocarbons and they need to be fully converted to CO2, N2 and H2O. Nanocrystalline noble metals Pt, Pd, Rh dispersed on oxide supports such as Al2O3 or SiO2 promoted by CeO2 form bulk of exhaust catalysts.
We have synthesized nanocrystalline, single phase, Ce1-xMxO2-δ and Ce1-x-
yTiyMxO2-δ (M = Pt, Pd, Rh; x=0.01 to 0.02, δ ~ x, y=0.15-0.25) oxides in fluorite structure. In these oxide catalysts, Pt2+, Pd2+ or Rh3+ ions are substituted only to the extent of 1 to 2% of Ce4+ ion. Lower valent noble metal ion substitution in CeO2 creates oxygen vacancy. Reducing (CO, H2, NH3) and oxidizing (O2, NO) molecules are adsorbed on electron deficient metal ions and electron rich oxide ion vacancy sites, respectively. The rates of CO and hydrocarbon oxidation and NOx reduction (with > 80% N2 selectivity) in presence of these ionic catalysts are 15 to 30 times higher compared to the same amount of noble metal loading on any oxide support. Palladium ion in CeO2 or Ce1-xTixO2 is far superior to Pt, Rh ionic catalysts and thus the expensive Pt and Rh metals can be dispensed away in favor of Pd in exhaust catalysts. By the same combustion method, nanocrystalline ionic catalysts are grown on ceramic cordierite and high performance in powder material is reproduced on the honeycomb catalytic converter. Oxygen in CeO2
lattice is activated by the substitution of Ti ion as well as noble metal ions due to the creation of longer Ti-O and M-O bonds than the mean Ce-O bonds leading to high oxygen storage/release property. The origin of promoting action of CeO2, activation of lattice oxygen and high oxygen storage capacity, metal support interaction and high rates of catalytic activity in exhaust catalysis is traced to the interaction between M0/Mn+, Ce4+/Ce3+ and Ti4+/Ti3+ redox couples.
IL-26
The using of synchrotron radiation time-resolved X-ray diffraction experiment for kinetic investigation of SHS with millisecond time
resolution.
B.P.Tolochko1, M.R.Sharafutdinov1, V.M.Titov2, V.V.Zhulanov2, A.S.Rogachev3
1-Institute of Solid State Chemistry and Mechanochemistry SB RAS, Novosibirsk, Russia
2-Budker Institute of Nuclear Physics SB RAS, Novosibirsk, Russia 3-Institute of Structural Macrokinetics and Materials Science, Chernogolovka, Russia
Email: [email protected] Abstract:
The synchrotron radiation (SR) is a powerful instrument for study of SHS. At the last decade progress in this area was determined by progress in development of new specialized generator of synchrotron radiations - wigglers and undulators, installed at 3-th generation storage rings [1]. So brilliance of SR is 1023 (photons/sec/mm2/mrad2 in 0.1% bandwidth) now and will reach 1035 (photons/sec/mm2/mrad2 in 0.1% bandwidth) in the nearest future.
High brilliance allows to realize the high time resolved diffraction experiment with millisecond time resolution now [2] and nano/femto- second time resolution in the nearest future. There are no chance to realize such experiments with using commercial X-ray devices. High time resolved diffraction experiment needs high count rate area detectors, which developed in last decade with big progress also [3,4].
Using of this method for SHS allows to receive new, inaccessible earlier information - about phase transformation in chemical reaction zone, about formation of an intermediate phases, about behavior of the reagents crystalline lattice before reactions, and about relaxation process after reaction.
At present time was reached following parameters of diffraction experiment for SHS: locality - 5 micrometers, time resolution - 1 ms, number of the frames - 1000.
The same systems was investigated in mode of SHS, and under slow heating up to the high temperature. It is found that in different case of the reactions was realized on different mechanism.
The progress in generations of SR opens the new possibilities for use of SR for study SHS: locality - 100 nm, time resolution - 1 microsecond/femtoseconds, depth of the penetration of the radiation - 1 sm.
References
1. Batrakov A., Borovikov V., Bekhtenev E., Fedurin M. et. al.. Magnetic measurements of the 10 T superconducting wiggler for the SPring-8 storage ring //Nuclear Instruments and Methods in Physics Research Sec. A: Vol. 467-468, Part 1, 21 July 2001, P. 190-193.
2. Sharafutdinov M., Alexandrov V., Evdokov O., Naumov D., Pirogov B., Pismenskaya E., Rogachev A., Tolochko B. The study of Ni + Al self-propagating high-temperature synthesis using synchrotron radiation and a two-dimensional DED-5 detector // Journal of synchrotron radiation. - 2003. - Vol. 10, No 5. - P. 384-386.
3. Aulchenko A., Zhulanov V., Shekhtman L., Tolochko B., Zhogin I., Evdokov O., Ten K. One-dimensional detector for study of detonation processes with synchrotron radiation beam // Nuclear instruments and methods in physics research. Sec. A. - 2005. - Vol. A543, No. 1. - P. 350-356.
4. Aulchenko V.M., Bukin M.A., et al., Fast, parallax-free, one coordinate X-ray detector OD3. Nuclear Instruments and Methods in Physics Research Section A:, A405 (1998), 269.
IL-27
Combustion synthesis of oxide materials for catalytic applications
G. Ranga RaoDepartment of Chemistry, Indian Institute of Technology Madras, Chennai 600 036,
IndiaEmail: [email protected]
Abstract:
Among various synthetic methods starting from aqueous solutions, combustion synthesis has turned out to be a quicker and simple method to synthesize pure oxide materials and oxide solid solutions for catalytic applications [1]. In wet combustion method, common and readily available inorganic reagents are employed as metal precursors in the presence of an organic fuel for combustion. This method has been perfected by Professor K. C. Patil in the last couple of decades. The method has been preferred over various traditional and sophisticated synthetic methods such as sol-gel, hydrothermal, micro-emulsion and co-precipitation for preparing catalytic oxides which find extensive applications in catalysis [2 -6] and fuel cells. New fuels such as N-tertiarybutoxy-carbonylpiperazine (C9H18N2O2) have been employed in our laboratory to prepare CuNi alloy particles [7]. References:
1. Chemistry of Nanocrystalline Oxide Materials : Combustion Synthesis, Properties and Applications by K.C. Patil, M.S. Hegde, T. Rattan and S.T. Aruna, World Scientific, 2008.
2. P. Bera, K.C. Patil, V. Jayaram, G.N. Subbana, M.S. Hegde, J. Catal 196 (2000) 293.
3. G. Ranga Rao, H.R. Sahu and B.G. Mishra, Colloid Surfaces A 220 (2003) 261.4. B. Murugan and A. V. Ramaswamy, J. Am Chem. Soc 129 (2007) 3062.5. G. Ranga Rao and T. Rajkumar, Catal. Lett. 120 (2008) 261.6. G. Ranga Rao and T. Rajkumar, J. Colloid Interface Sci. 324 (2008) 134. 7. G. Ranga Rao, B.G. Mishra and H.R. Sahu, Mater. Lett. 58 (2004) 3523.
IL-28
Peculiar properties of the combustion process and structure formation in Ti-Ta-C system
Kurbatkina Victoriya1, .Levashov Eugeny 1, Patsera Yevgeniy1,Rogachev Alexander2, Kochetov Nikolay2, Sachkova Nina2
1- Scientific-Educational Center of SHS- State Technological University Moscow Institute of Steel and Alloys, Russia, 119049 Moscow, Leninsky prospect 4,
2- Institute of Structural Macrokinetics, Russian Academy of Sciences, Chernogolovka, Moscow Region, 142432 Russia
Email: [email protected]:
The macrokinetic peculiar properties of combustion process have been studied of mixtures in (100-x)(Ti+0.5C) + x(Ta+C) system with varying the mixture parameter (x) and initial temperature (To) of charge heating. Sharp increase in the combustion rate (Uc) and temperature (Tc) has ben found for the compositions having x=10 and 30% as result of proceeding two parallel reactions of titanium and tantalum carbide formation. The Uc(To) and Tc(To) dependencies are linear for the mixture with x = 50%. Using the combustion wave quench hardening, it was found that the primary structure formation in the combustion zone begins with precipitation of the submicrometer grains of non-stoichiometric titanium carbide from supersaturated solid solution. The synthesis products are single-phase and represent (Ti,Ta)C – titanium-tantalum carbide within investigated range of x parameter. Increase of x results in decreasing (Ti, Ta)C grain size and microhardness as well as in reducing the relative density of compact synthesis products. The kinetics of high-temperature oxidation of (Ti,Ta)C carbide based alloys has been investigated. Ceramics produced at x=10% possesses the highest heat-resistance.
IL-29
Combustion Synthesis & Characterization of Luminescent Materials-A Review
R. Gopi Chandran
Materials Characterization LabGE Global Research
John F Welch Technology CentreEPIP-2, Plot # 122, Whitefield Road
Bangalore 560066, IndiaEmail: [email protected]
Abstract:
This presentation would review the published literature on the Self-propagating High Temperature Synthesis & Characterization of Luminescent Materials. The focus of this presentation would be to discuss the various lighting technologies, highlighting the importance of phosphor materials in light conversion, as well as touch upon the challenges & potential of combustion synthesis.
IL-30
Nebulized Spray Pyrolysis coupled with Chemical Vapor Synthesis to produce high surface are nanoparticles with unusual properties
Raju Addepalle RaghuramaHoneywell Technology Solutions Lab Pvt. Ltd., Bangalore-560 226, India
Email: [email protected]:
Nebulized spray pyrolysis is a novel technique to synthesize spherical and hollow particles of many materials. Chemical vapor synthesis is also a novel process to synthesize nanopowers and films of variety of materials. Combining these two techniques, one can synthesize new forms of materials of hollow spheres decorated with nanosize particles on the surfaces. Nanocrystalline powders of pure Sm2O3 and doped with MgO are prepared by NSP combined with CVS and using aqueous precursor solutions containing citric acid as a complexant. As prepared powders consists of hollow spheres with thin shells consisting of nanocrystalline powders. The two phase samples exhibit an improved micro-structural stability compared to pure Sm2O3. The microstructure before and after various heat treatments have been investigated using high resolution TEM, SEM, nitrogen adsorption and X-ray diffraction studies.
IL-31
Rare-earth Sulfide Pigment by Solution Combustion MethodArun M Umarji, G.P.Shivakumara, Basavaraj Angadi and K.C.Patil,
Materials Research CentreIndian Institute of Science, Bangalore 560012 INDIA
Email: [email protected]
Abstract:The limitations on the use of heavy elements based ceramic pigments have given
an impetus to the search for new inorganic and non-toxic pigments, particularly on the red and yellow colored range. Some of the commercially available red and yellow pigments such as cadmium sulfoselenide are known to be environmentally hazardous due to their high toxicity. The rare earth sulfides based ceramic pigments received much attention for their environmental benignness and for their high thermal and chemical stability [1]. Rare earth elements and sulfur combine to form a wide range of compounds as sulfides or oxy sulfides [2]. Among them sesquisulfides appeared to have the best potential as for as the color is concerned.
Here we present the preparation of rare earth sulfides and oxysulfide pigments by the combustion of aqueous solution containing Rare earth nitrate and thiourea redox mixture in a specially designed Bell jar and Tubular furnaces. The formation of sulfide and oxysulfide phases was facilitated by creating oxygen free and sulfur rich environments. The crystallinity and phase composition of Ce2S3, Ce4O4S3 brownish red pigments, La2O2S yellow pigments prepared by bell-jar method and Nd2O2S light green and Pr2S3 deep brown pigments prepared by tubular furnace method were confirmed by X-ray diffraction technique through standard JCPDS patterns. The colour and brightness of the rare earth sulfides were determined by means of L* a* b* parameters using UV visible spectrometer fitted with an integrated sphere. Acknowledgement: Authors sincerely thank Council of Scientific and Industrial Research, New Delhi, Govt. of India, under NMITLI program, for their financial support.Ref:[1] R.Mauricot, P.Gressier, M. Evain, R.Brec. J. Alloys Compds, 302 (2000) 118-127.[2] G.Buxhamm, Industrial Inorganic pigments Vol.2nd Edition, 1998,Eeinheim Germany: VCH
PO-01
High Oxygen Storage Capacity and high rates of CO oxidation and NO reduction catalytic properties of Ce1-xSnxO2 and Ce0.78Sn0.2Pd0.02O2-
Asha Gupta, T. Baidya, Parag Deshpande, Giridhar Madras and M. S. HegdeSolid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore-560012,
Abstract:
Ce1-xSnxO2 (x = 0.1-0.5) solid solution and its Pd substituted analog have been prepared by single step solution combustion method using tin oxalate precursor. The compounds are characterized by XRD, XPS, TEM and H2/TPR studies. Cubic fluorite structure remains intact up to 50% of Sn substitution in CeO2 and compounds are stable up to 700 0C. Oxygen storage capacity of Ce1-xSnxO2 is much higher than Ce1-xZrxO2 due to accessible Ce4+/Ce3+ and Sn4+/Sn2+ redox couples at temperatures between 200 to 400 0C. Pd2+ ion in Ce0.78Sn0.2Pd0.02O2- is highly ionic and lattice oxygen of this catalyst is highly labile leading to low temperature CO to CO2 conversion. Rate of CO oxidation is 10 μmoles g-1sec-1 at 60 0C. NO reduction by CO with 70% N2 selectivity is observed at 200 0C and 100% N2 selectivity below 250 0C with 1000 to 5000 ppm of NO. Pd2+ ion substituted Ce1-xSnxO2 is a far superior catalyst compared to Pd2+ ions in CeO2, Ce1-xZrxO2
and Ce1-xTixO2 for low temperature exhaust applications due to involvement of Sn2+/Sn4+
redox couple along with Pd2+/Pd0 and Ce4+/Ce3+ couples.
PO-02
Nano-Structure materials by sol-gel process for various industrial applications
A.R. Phani1*, S. Shankaran2, S. Santucci3, S. S: Srinivasan4 and E. Stefanakos1 Nano-RAM Technologies, Bangalore, India
2 Manipal Institute of Technology, Manipal University, Manipal, India3 CASTI-CNR Regional Laboratory, University of L’Aquila, L’Aquila, Italy
4 CERC, University of South Florida, Tampa, Florida, USAEmail: [email protected], [email protected]
Abstract:The nanotechnology is considered to have great potential for the development of
new innovative materials with an environmental advantage, the so-called ‘eco-innovation’ materials. However, it is necessary to have in-depth project in this area, in order to facilitate and not at least to accelerate implementation of nanocoatings or nanomaterials in different end products. The nanotechnology is still in the early development stage, where great potentials are discovered, but where it at the same time is difficult to get support from other scientists and materials developers and heading forward to actual product innovation projects. Nanostructured materials are expected to create radical changes in diverse fields. From electronics, by providing materials for the next generation of computer chips; to energy technologies, where novel materials may have a critical impact on new types of solar cells, rechargeable batteries and energy storage systems. Potential applications for micro and nanostructured materials include pharmaceuticals, cosmetics, medical diagnostics, catalysts and supports, membranes and filters, batteries and fuel cells, hydrogen storage systems, electronic, magnetic and optical devices, flat panel displays, biomaterials, drug delivery systems, structural materials and protective coatings. To meet the requirements, the sol-gel process represents a flexible chemical route to synthesize various high performance nanostructured ceramic materials with controlled internal morphology and chemistry. Materials with designed internal nanostructure (entirely interconnected open nanoporosity, hierarchical, fractal or nanocrystalline solid network), and various possible chemical compositions (from organic to inorganic) can be processed and designed through a large range of shapes (finely divided nanopowders, nanoparticles, thin and thick films, fibers, granular beds and monolithic materials). The sol-gel process is a solution-based technique, where the material structure is created through chemical reactions in the liquid state, giving the high
flexibility of the process for easy application. In the present work it will be demonstrated that sol-gel technology can alone bring all the nanomaterials (nanostructured thin films, nanostructurted coatings, aerogels, hydrogels, xerogels, nanoparticles, nanofibers, nanospheres) to apply to various industrial applications that include energy, transport, health, food, life sciences.
Keywords: Sol-gel process, nanostructures, thin films, nanoparticles, nanospheres,
nanofibers, antibacterial, photocatakytic, anticorrosion, gas sensors,
PO-03
Combustion synthesis and color evolution studies of Praseodymium doped Ceria: Environmentally safe red pigments
Basavaraj Angadi1,3, K. C. Patil2, A. M. Umarji2
1Department of Physics, Bangalore University, Jnanabharathi, Bangalore – 560 0562Inorganic and Physical Chemistry Department, Indian Institute of Science, Bangalore –
560 0123Materials Research Centre, Indian Institute of Science, Bangalore – 560 012
Email:[email protected]:
The rare earth based ceramic pigments have been studied extensively ever since they proved their potentiality as an environmentally safe and high temperature pigments. Among them the Praseodymium doped Ceria gives new stable red color[1]. The praseodymium doped ceria, Ce1-xPrxO2- (x = 0.00 to 0.10), red pigments were prepared by solution combustion method using different precursors. The effect of various precursor combinations (oxidizer and fuel), Pr doping and sintering on the crystallite size, microstructure and colour properties (L*, a*, b*) of Ce1-xPrxO2- pigments were investigated. The as prepared pigment powders with the particle size in the range of 10 – 30 nm showed pure fluorite phase of CeO2 and exhibit good color properties. The 2% Pr doping and sintering at 1000 C for 1 hour was found to be optimum conditions for better pigment properties with L*, a*, b* values of 58.962, 24.690, 31.881 respectively.
Acknowledgements : The authors are thankful to the Council of Scientific and Industrial Research (CSIR), India for the financial support.
Reference:[1] S.T. Aruna, S. Ghosh, and K.C. Patil, Int. J. Inorg. Mater., 3 (2001) 387.
PO-04
Thermoluminescence Studies of Low-Temperature Synthesis of Dicalcium silicate
Chikkahanumantharayappa1* and B.M. Nagabhushana2, B.N. Lakshminarasappa3
Department of Physics, Vivekananda Degree College, Bangalore – 560 055Department of Chemistry, M.S. Ramaiah Institute of technology, Bangalore – 560 054
Department of Physics, JB campus, Bangalore University, Bangalore -560 056
Email: [email protected]:
Beta-dicalcium silicate (C2S) is an important constituent of Portland cement clinker, glages, pigments, bioactive material etc. C2S of pure and doped with La, Gd, Cr and sulphosilicate nano powders were synthesized by low temperature initiated novel solution combustion method. The influence of calcinations temperature on the average crystallite size, specific surface area, thermo gravimetric analysis, morphology of the powder were studied by X-ray diffraction technique (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and N2 adsorption measurements (BET). It is observed that as the calcinations temperature increases from 500-1200oC the crystallite size increases and the specific surface area decreases. Thermoluminesce (TL) of C2S using gamma irradiation ranging from 1Gy-108KGy has been studied. Two prominent TL glow peaks recorded in pure, Gd, Cr and sulphosilicates and three glow peaks were observed in La doped C2S powder. TL intensity varies linearly with dose. The enhancement of TL intensity and shifting of glow peak temperature with heating rate and activation energy, frequency factor were calculated. Enhancement of TL intensity in La and Gd doped C2S powder is due to luminescence activators and quenching due to Cr in Cr doped C2S systems. In sulphosilicates two dosemetric peaks one at ~190 and another at ~376oC are recoded and compared with standard LiF TLD phosphor. TL intensity two and half times more than that of LiF were recorded and the defect studies were made by ESR step annealing technique.
PO-05
Spectroscopic studies of Y2O3: Sm3+ nanophosphor prepared by low-temperature solution combustion
J.R. Jayaramaiah1*, B.N. Lakshminarasappa2, B.M. Nagabhushana3, Chikkahanumantharayappa4, H. Nagabhushana5
1Department of Physics, Global Academy of Technology, Bangalore -560 0982Department of Physics, JB campus, Bangalore University, Bangalore -560 056
3Department of Chemistry, M.S. Ramaiah Institute of technology, Bangalore -560 0544Department of Physics, Vivekananda Degree College, Bangalore - 560 055
5Department of PG studies in Physics, Govt. Science College, Tumkur-572 102Email: [email protected]
Abstract:The trivalent samarium doped Y2O3 Nanoparticles of with attractive
photoluminescent properties were prepared using ethylenediaminetetra acetic acid (EDTA) as fuel and Yttrium nitrate as oxidizer. The final product was characterized by PXRD, SEM, FTIR, surface area etc. The PXRD pattern reveals cubic in phase, which are directly obtained without further heat-treatment. The crystallite size was evaluated from broad PXRD peaks using Scherer’s formula and found to be in the range 20-30 nm. SEM images show agglomerations and foamy products due to large amount of gases expelled during reaction. FTIR spectrum of Y2O3: Sm3+ samples shows broad bands due to stretching frequency of Y-O can be observed below 700 cm-1. The bands between 3100-3800cm-1 may be due to -OH stretching of water molecules. Photoluminescent studies of Y2O3: Sm3+ system showed the characteristic emission narrow lines containing (J+1/2) manifolds of intraconfigurational 4G5/2 6HJ transitions (J=5/2, 7/2, 9/2 and 11/2) of Sm3+ ion with the 4G5/2 6H7/2 transition (~609nm) as a prominent intensity. Thermoluminescence and defect studies by means of ESR were also carried out and discussed in detail.
PO-06
Synthesis of Nanosize Co0.5Zn0.5Fe2O4 by Combustion and Precursor combustion Technique
Lactina R. Gonsalves1 and V.M.S.Verenkar1
1Department of Chemistry, Goa University, Taleigao Plateau, Goa-403206, IndiaEmail: [email protected]
Abstract:Magnetic nanoparicles continue to fascinate researchers not only for its
application potential but also for fundamental research. In the present study, a novel precursor, cobalt zinc ferrous fumarato-hydrazinate Co0.5Zn0.5Fe2O4. The precursor was characterized by IR, TG-DTA and was analysed for its hydrazine content. The novelty of this precursor is that, it decomposes autocatalytically to five uniform nanosized particles. X-ray investigations, of ‘as prepared’ ferrite confirmed the formation of single spinel phase. TEM confirmed the particle size to be ~20nm. The ‘as prepared’ ferite has a low value of saturation magnetization, which increases with the sintering temperature; this can be attributed to the nanosize nature of the ferrite particles. The ferrite was then sintered at 10000C for 15h. and was characterized by XRD, IR, SEM, TEP, DC electrical resistivity and saturation magnetization measurements. The saturation magnetization values of sintered oxide matches with the reported one. The Seebeck coefficient measurement upto 3000C shows n-type conductivity. The SEM of the sintered oxides shows particles in the range of 2-5 microns. The Tc of the sintered ferrite closely matched with the reporter value.
Co0.5Zn0.5Fe2O4 oxide has also been prepared by combustion method using hexamine as the fuel with variable fuel oxidizer ratio. The fuel deficient mixture gave the ‘as prepared’ ferrite with small particle size and high surface area. XRD investigations, confirmed the formation of single spinel phase for only two fuel deficient mixtures. The saturation magnetization value was found to be very low indicating small paricle size. The ‘as prepared’ oxide was characterized by IR, DC electrical resistivity, TEP and BET Surface Area Analyser.
References:1] V.M.S.Verenkar and K.S. Rane, ‘Proc.12th Nat. Symp. On Thermal Analysis’, Mumbai, India (1995) 175
2] R.A.Porob, S.Z. Khan, S.C. Mojumdar and V.M.S.Verenkar, J. Therm.Anal. Cal., 86 (2006) 6053] S.Y.Sawant, V.M.S.Verenkar and S.C. Mojumdar, J. Therm.Anal. Cal., 94 (2008) 1, 63-67
PO-07
Synthesis and surface properties of ceramic alumina-nanocomposite coatings by High temperature electrolytic oxidation-a cost effective
approach
V. Raj* and M. Mubarak AliDepartment of Chemistry, Periyar University, Salem-636011, Tamil Nadu, India
*E-mail:[email protected]:
A dense alumina ceramic nanocomposite oxide coating was prepared on aluminium by electrolytic anodization technique using a novel electrolyte system at higher temperature than reported previously. Electrolytic oxidation was carried out on aluminium in silicate containing alkaline bath at various forming voltages ranging from 30-60 V at 20-400 C for various durations. Thickness, hardness, rate of growth of the coating and coating ratio were measured using faraday’s law and mass measurements. The effect of anodization parameters on the surface properties and the growth kinetics were studied in detail. The surface morphology, element and phase composition of the formed ceramic alumina nanocomposite coatings were characterized by scanning electron microscopy (SEM), Energy Dispersive spectroscopy (EDS) and X-ray diffractometry (XRD) respectively. This facilitates maintaining mechanical properties of pure aluminium after anodic oxidation treatment on aluminium surface. Results promote the knowledge on growth mechanism and kinetics of anodic films enabling methods to optimize the better design of structure for their many scientific or technological applications.
Keywords: Ceramic, Aluminium, Hardness, Anodization, XRD.
PO-08
Combustion synthesis, characterization and study of magnetic properties of alkaline earth substituted lanthanum manganites
B.M. Nagabhushana1*, R.P. Sreekanth Chakradhar2, K.P. Ramesh3, V. Prasad3, C. Shivakumara4,
G.T. Chandrappa5*
1Department of Chemistry, M.S. Ramaiah Institute of Technology, Bangalore 560 054, India
2Glass Technology Laboratory, Central Glass and Ceramic Research Institute, Kolkata, India
3Department of Physics, Indian Institute of Science, Bangalore 560 012, India4Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560
012, India5Department of Chemistry, Central College Campus, Bangalore University, Bangalore
560 001, India
Email: [email protected], [email protected]:
The alkaline earth doped manganites are interesting in terms of their magnetoresistance (MR) studies and applications. The nanocrystalline colossal magnetoresistance (CMR) compounds LaMnO3+ and La1-xAxMnO3+ (where A= Ca, Sr and Ba; with x = 0.1 x 0.5 for Ca, and x = 0.0 x 0.3 for Sr and Ba doping) have been prepared by low temperature solution combustion synthesis using corresponding metal nitrates as oxidizers and oxalyl dihydrazide as a fuel at relatively lower temperature (~300 oC). The combustion derived samples have been characterized by various techniques. The metal-insulator transition studies on all compounds and MR property of selected samples have been systematically studied. The samples sintered at 900 C exhibit a broad metal-insulator transition including LaMnO3+ (TM-I = 222 K), which is absent in the sample prepared by solid state route. The TM-I values shift to lower temperatures on doping and these values are lower compared to the samples prepared by high temperature method. The low temperature resistivity measurements show negative MR and exhibit field-induced ferromagnetic orderings. It is also observed that the resistance decreases with increasing magnetic field and TM-I shifts towards higher temperature. This is due to the fact that the applied magnetic field induces delocalization
of charge carriers, which in turn might reduce the resistance and also cause the local ordering of the magnetic spins.
PO-09
Luminescence properties of swift heavy ion irradiated solution combustion synthesized mullite phosphor
H. Nagabhushanaa*, B.M. Nagabhushanab B.N. Lakshminarasappac, G. Satish Babud, Fouran Singhe,
a Department of PG studies in Physics, Govt. Science College, Tumkur-572 103, IndiabDepartment of Chemistry, M.S. Ramaiah Institute of Technology, Bangalore-560 0054,
Indiac Department of Physics, Jnana Bharathi Campus, Bangalore University, Bangalore - 560
056, India.d Department of Physics, Govt. College for Women, Chintamani-563125, India
e Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi - 110 067, India. *Email: [email protected] (H. Nagabhushana)Abstract:
Mullite (3Al2O3.2SiO2) is an aluminum silicate, a promising material for high temperature applications due to its low thermal conductivity. The silicate group of this material is used in the production of non-fusion cast tank blocks, manufacture of spark plugs etc. Nanocrystalline mullite phosphor has been synthesized by a novel low-temperature initiated self propagating, gas producing solution combustion process and final products are characterized by PXRD, SEM, EDS, porosity, surface area measurements etc.
Photoluminescence (PL) studies of mullite phosphor was studied with 100MeV swift Ag+8 and Si+8 ions in the fluence range 11011- 5 1012 ions cm-2 at RT with different He-Cd laser excitation wavelengths. In Ag+8 ion irradiated sample, a pair of PL bands, one broad band centres at ~550nm and another sharp one at ~ 690nm is observed with excitation by a 442nm laser beam. In 326nm laser beam excitation, three bands with peaks at ~ 460, 550, and 760nm are observed. However, in Si+8 bombarded sample, two well resolved PL bands with peaks at ~764 and 538 nm and weak peaks at ~400, 464 and 733 nm have been recorded with 442 nm laser beam excitation. On the other hand when the sample is excited with 336 nm laser beam three characteristic PL bands with peaks at ~710, 538, 401, 693 and 710 nm are recorded. It is observed that the PL intensity increases up to a fluence of 5x1011 ions/cm2 and thereafter it decreases with increase of Ag ion fluence. Whereas in Si+8, the PL intensity increases with increase of ion fluence. The decrease in PL intensity is attributed to Al-O and Si-O type species present on the
surface are getting amorphized. The increase in intensity is due to O-Si-H type species covered on the surface of the sample. Further, the oxygen atom could passivate the silicon dangling bonds there by reducing the probability of non-radiative recombination centers as a result the PL intensity increases. Thermoluminescence studies were also carried out with same ion fluence and energy and results are compared to gamma irradiated samples.
PO-10Ionoluminescence of Dy3+ doped aluminum oxide
K.R. Nagabhushana12, B.N. Lakshminarasappa2* and Fouran Singh3
1P.E.S. Institute of Technology, 100 Ft Ring Road, BSK III Stage, Bangalore-5600852Department of Physics, Jnanabharathi Campus, Bangalore University, Bangalore-560 056
3Inter University Accelerator Centre, P.B. No. 10502, New Delhi-110 067 Email: [email protected]
Abstract: Aluminum oxide (Al2O3) is one of the standard radiation resistant materials used
under various radiation environments. Also, nanocrystalline aluminum oxide finds wide applications as sensors, catalysts, coating materials, thermoluminescence dosimeters (TLD’s) etc. Ionoluminescence of pure as well as Dy3+ doped nanocrystalline aluminum oxides synthesized by combustion technique have been studied and the results obtained are presented here. Aluminum nitrate, ammonium nitrate and glycine are in the combustion process. The XRD pattern of the synthesized sample indicted the -phase. Transmission electron microscopy results revealed the particle sizes in the order of ~ 25 nm. Ionoluminescence (IL) studies are carried out using 100 MeV swift Si7+ ions. A prominent emission with peak at 695 nm along with the weak emissions at 420, 640 and 710 nm is observed in pure nanocrystalline aluminum oxide. In Dy3+ doped nanocrystalline aluminum oxide, characteristic emission in the range 475-500 nm with peak at 493 nm and 525 - 600 nm with peak at 588 nm is observed. However, in doped Al2O3 it is noticed that the 420 nm emission is not observed probably due to over lapping with 475 -500 nm emission while the 695 nm emission is very weak . The emission observed at 695 nm is attributed to the extrinsic luminescence of Cr3+ impurities which is invariably present in the sample. The 420 nm emission is attributed to F-centers generated due to energetic swift heavy ions. The spectral peaks at 493 nm and 588 nm correspond to and transitions of Dy3+ respectively.
Key words: Nanocrystalline Al2O3, Combustion synthesis, Ionoluminescence.
*
PO-11
Combustion derived MgO for the removal of adsorbable organic halides (AOX) and total organic carbon (TOC) from paper mill effluent
B. Nagappa1,2* and G. T. Chandrappa2
1Karnataka State Pollution Control Board, “Parisara Bhavana” # 49, Church Street, Bangalore – 560001
2Department of Chemistry, Central College Campus, Bangalore University, Bangalore-560001
*e-mail: [email protected]:
It has been demonstrated that nanocrystalline metal oxides especially MgO, CaO and ZnO have unparallel sorption properties for polar organics and other chemical species [1]. In addition, since MgO is known to adsorb a wide range of organic and inorganic pollutants, it was synthesized using various processes/methods. Among several methods, low temperature initiated self propagating gas producing combustion process [2] was used for the synthesis of MgO using glycine as fuel and magnesium nitrate as oxidizer. The combustion product was characterized by PXRD, SEM/TEM and surface area. As made MgO was used as adsorbent for the removal of adsorbable organic halides (AOX) and total organic compound (TOC) from paper mill effluent. The pulp and paper industry is water intensive in terms of freshwater withdrawal; about 60-100 M3 of water is required to produce a ton of paper resulting in the generation of large volumes of waste water. It is discharging a variety of gaseous, liquid and solid wastes [3] of the different waste streams. Bleach plant effluents are most toxic due to various chlorinated organic compounds generated during the bleaching of pulp. In waste water, these compounds are estimated collectively as AOX. The pollution removal process can be globally measured with COD, BOD or TOC. Adsorption is a useful tool for removing the aqueous AOX and TOC pollution. Batch shaking process was performed using MgO as adsorbent with effluent collected from pulp and paper mill to remove AOX and TOC. The data reveals that ~92 % of AOX and ~ 87 % of TOC could be removed. In this process, waste (sludge) generation can be minimized up to 90 %.
Key words: Combustion process, metal oxide, environmental pollutants
References1 E.Lucas, S. Decker, A. Khaleel, A. Seitz, S. Fultz, A. Ponce, W. Li, C. Carnes, and K. J. Klabunde Chem. Eur. J. 7 (2001) 2505.2 K.C. Patil, in: S.T. Aruna, P. Bera, M.S. Hedge (Eds.), Nanomaterials in Environment
Protection and Remediation, Research Signpost, Trivandrum, India, 2003, pp. 72–73.3 Kaustubha Mohanty, J. Thammu Naidu, B. C. Meikap and M. N. Biswas, Ind. Eng.
Chem. Res. 45(2006) 5165.
PO-12
Production of Hydrogen via Biomass Route:
Design and Fabrication of a Robust Multi-scale System for Continuous Monitoring of Syn-Gas Treatment Using Different Packed Bed Reactors
Parag A. Deshpande1, Sudhanshu Sharma2, Giridhar Madras1, M.S.Hegde2
1 Dept. of Chemical Engineering 2 Solid State and Structural Chemistry Unit
Indian Institute of Science, BangaloreAbstract:
We focus our attention on the production of hydrogen from alternative resources mainly the biomass. Water gas shift reaction has been made use of for manufacturing hydrogen from carbonaceous matter in industries for a long time. We have developed new catalysts such as Ce1-xMxO2-δ, Ce1-x-yMxNyO2-δ (M = Pt, Pd; N = Ti, La) synthesized by solution combustion technique to obtain hydrogen from CO and steam by water gas shift:
(1)
We have also been successful in coating the catalysts over the ceramic honeycombs by the same solution combustion method. The systems for catalytic testing and gas monitoring has been fully set up with its specialty that it can be used for the regular lab-scale testing as well as for scaled up processes. The system has facility of using catalysts in different forms (granules, pallets, monoliths etc) and can be operated with a wide range of gas flow rates. High CO conversions have been obtained on the system with conversions reaching near 100% in some cases. Catalytic testing for determining the catalyst deactivation on long time basis has been conducted on the system proving its robustness of operation. We have found that the combustion synthesized compounds such as Ce1-xPtxO2-δ show high catalytic activity without methane formation.
PO-13
Green-light emitting long-lasting phosphorescence in SrAl2O4:Eu2+, Dy3+
phosphor
H. B. Prem Kumar 1, H. Nagabhushana2*, B.M. Nagabhushana3, Chikkahanumantharayappa4
1 Department of Physics, Sri Bhagawan Mahaveer Jain College, Bangalore – 560 027, India
2 Department PG studies in Physics, Govt. Science College, Tumkur -567 172, India3Department of Chemistry, M.S. Ramaiah Institute of Technology, Bangalore 560054,
India4Department of Physics, Vivekananda Degree College, Bangalore 560 055, India
Email: [email protected]
Abstract:Long lasting phosphors can light up for a long time in the darkness after
irradiation with sunlight or artificial light. Eu2+, Dy3+ co-doped alkaline earth aluminates have been regarded as useful phosphors that have higher brightness, longer lifetime and better chemical stability. Combustion synthesis of SrAl2O4:Eu2+, Dy3 long-lasting phosphor was prepared using oxalyl dihydrazine (ODH) as fuel and corresponding metal nitrates as oxidizers. An efficient phosphor can be prepared by this method in a muffle furnace maintained at 350 ºC in a very short time. The phosphor is characterized by Powder X-ray diffraction (PXRD), Scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS), BET surface area, porosity etc. PL spectrum revealed that europium ions were present in divalent oxidation state and dysprosium ions were present in trivalent state. After irradiation by a 254 nm UV lamp or conventional florescent lamp for 5 min the phosphor emits green light emitting long lasting phosphorescence for more than 3 hrs even after the irradiation source has been removed. A possible mechanism of the lasting phosphorescence based on Thermoluminescence and Electron spin resonance results are proposed.
PO-14Synthesis and characterization of FeZnO4 and CoFeO4 prepared
through Self Propagating Combustion RoutePrithviraj P.M., Basawaraja S, Nijagunappa R and Venkataraman A*
Materials Chemistry Laboratory, Department of Materials Science, Gulbarga University, Gulbarga-585 106
Email: [email protected]
Abstract:
The ferrites having the general molecular formulae FeZnO4 and CoFeO4 have been synthesised by employing self propagating low temperature combustion route using polyethylene glycol (mol.wt. 4000) as a fuel. The XRD results show monophasic structures and the morphology of the oxides are mostly spherical with some agglomeration. The high surface area of these samples also indicates their stability for a catalytic reaction apart from their potential semiconducting applications.
PO-15
Ionic Palladium catalyzed Carbon-Carbon Coupling Reactions
Sanjaykumar S. R., Satish Patil, Bhaskar D. Mukri and M. S. HegdeSolid State and Structural Chemistry Unit,
Indian Institute of Science, Bangalore–560012 Abstract:
Ceo.98 Pdo.o2 O2-δ catalyst has been prepared by solution combustion method. Ceo.98
Pdo.o2 O2-δ was shown to be effective catalyst for Carbon-Carbon coupling reactions of bromoarenes in DMF. These Carbon-Carbon coupling reactions are in high yield under mild conditions. A wide range of substrates has been screened including the less active bromoaryl compounds.
PO-16
Synthesis of microcrystalline CeAlO3 by a novel solution- combustion route
Satish ShettyChemistry and Physics of Materials Unit, JNCAR, Bangalore
Email: [email protected]:
We have synthesized CeAlO3 by a novel solution combustion technique using a mixture of urea and glycine as fuel.High quality single phase polycrystalline CeAlO3 was obtained by optimising the fuel ratio. The transmission electron micrograghy and powder x-ray diffraction investigations show that the particles are microcrystalline in size. The sample is paramagnetic in the temperature range 100K-300K and fits curie Weiss model with p=40K.The value of eff=2. is close to that expected for a Ce3+ ion. The magnetic properties are similar to that reported for single crystals indicating the high quality of our samples .The sample is a semiconductor with a band of 2.77eV as estimated from UV-Vis spectroscopy.
PO-17
Novel catalysts synthesized by solution combustion method for water gas shift reaction
Sudhanshu Sharma1, Parag Deshpande2, Giridhar M2. And M. S. Hegde1
1Solid State and Structural Chemistry Unit, 2 Chemical Engg. Dept.Indian Institute of Science Bangalore India
Abstract:
Due to growing demand for the polymer electrolyte fuel cell (PEFC) for small scale power source, sources of pure hydrogen has become important. Syngas containing CO and H2 from the controlled combustion of biomass is a renewable source of carbon and hydrogen and if CO can be converted efficiently, biomass forms the source of hydrogen. Therefore, development of efficient catalysts for water gas shift (WGS) reaction (CO + H2O → H2 +CO2 ; ΔH = -41.1 KJ) is critical. Combustion synthesized nanocrystalline catalysts Ce1-xPtxO2-δ (I), Ce1-x-yTixPtyO2-δ(II), TiPtxO2-δ(III) have been tested for the water gas shift reaction with 2vol% CO and 30vol% H2O with and without the presence of excess hydrogen. Each of the catalyst was found efficient for the WGS reaction and nearly 99.5% CO conversion has been achieved. These catalysts are free from deactivation due to carbonate formation during the long run reaction conditions. While Ce1-xPtxO2-δ gave 20 to 30 ppm of CH4 in presence of excess H2, other two catalysts did not show formation of methane. Activation energies with catalysts I, II and III are 15, 13.5 and 10 kcal/mol respectively.
PO-18
Ultrasonic nebulised spray pyrolysis of an aqueous combustion mixture for the deposition of ZnO thin films for gas sensing
Ujwala Ail, S. A. Shivashankar and A. M. UmarjiMaterials Research Centre, Indian Institute of Science, Bangalore – 560 012
Email: [email protected]:
Zinc oxide (ZnO) is one of the technologically important oxide semiconductors with promising applications in gas sensing, UV photonics, surface acoustic wave devices, piezoelectric transducers, solar cells etc. Various techniques have been reported for the deposition of ZnO thin films [1-3].
Nebulized spray pyrolysis is a technique in which the precursor solution is nebulised with the ultrasonic nebulizer to give uniformly distributed micron and submicron sized droplets and the generated vapour is transported to the heated substrate by the carrier gas. The reactants pyrolyse on the substrate, the heterogeneous reaction leading to the formation of a thin solid film.This is an energetically economic, simple, fast process with control over homogeneity and stoichiometry of the film. Here we report the deposition of ZnO thin films by ultrasonic nebulised spray pyrolysis of an aqueous combustion mixture and study of their gas sensing properties.
Thin films of zinc oxide are deposited using nebulised spray pyrolysis of the combustion mixture containing stoichiometric amount of zinc nitrate and urea in aqueous medium. This solution (0.67M) is nebulised by the ultrasonic nebuliser and the fine droplets formed are carried to the hot substrate with the help of the carrier, nitrogen gas. As the droplets reach the substrate pre- heated to 500oC, self-propagating high temperature reactions take place to give crystalline, uniform film with unique microstructure. Details of the deposition and their characterization will be presented. The gas sensing property of the films was studied using a home-made setup designed for measuring the variation of resistance of the thin film, exposed to pulses of sensing gas at different controlled temperatures. The measurements were done in the temperature range 25oC- 400oC and the gases tested were aliphatic and aromatic hydrocarbons. It is found that the films are highly selective towards aliphatic hydrocarbons. The differences in the crystallinity, microstructure of the films deposited with and without urea suggest that the
combustion process leads to unique surface properties which give better gas sensing characteristics.
References:
1. F. Paraguay D et.al, Thin Solid Films 350 (1999) 192-2022. M. H. Aslan et.al, Solar Energy Materials & Solar Cells 82 (2004) 543–5523. Preetam Singh et.al, Journal of Crystal Growth 306 (2007) 303–310
.
PO-19
Combustion synthesis, characterization and luminescence studies of undoped and doped mesoporous Nd2O3
B. Umesh1*, B. Eraiah2, B.M Nagabhushana3, H. Nagabhushana4, Chikkahanumantharayappa5, C. Shivakumar6, R. P. Sreekanth Chakradhar 7
1Department of Humanities, PVP Polytechnic, Dr. AIT Campus, Bangalore 560056, India
2Department of Physics, Bangalore University, Banagalore 560 056, India 3Department of Chemistry, M.S. Ramaiah Institute of Technology, Bangalore-560 054,
India4Department of PG studies in Physics, Govt. Science College, Tumkur -572 102, India
5Department of Physics, Vivekananda Degree College, Bangalore 560 055, India6Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, India 7Glass Technology laboratory, Central Glass and Ceramic Research Institute, Kolkata-
700031 India Email: [email protected]
Abstract:
Rare earth oxides (RE2O3) have been of great scientific and technological interest for many years because of their attractive physical and chemical properties. Among these Nd2O3 have been widely used in photonic applications, luminescent materials, catalysts and protective coatings. Nanocrystalline undoped Nd2O3 and cobalt doped (1-4mol %) Nd2O3 were synthesized by low-temperature solution combustion technique using oxalyl dihydrazine (ODH) as fuel and neodymium nitrate as oxidant. The final products were characterized by a series of different physiochemical techniques such as PXRD, SEM, FT-IR, BET surface area, EDX, diffuse reflectance etc. The powder X-ray diffraction patterns show cubic structure which are directly obtained by the combustion process without further calcinations. The crystallite size was calculated by broad X-ray diffraction peak and found to be in the range 10-20 nm (Scherrer’s formula). SEM photographs reveals agglomerated, fluffy, fine and porous in nature. The N2 adsorption-desorption isotherms of the calcined (500°C) samples exhibited single hysteris loop with IUPAC IV type pattern indicating the existence of foremost mesopore. Photoluminescence, Thermoluminescence and Electron spin resonance studies of as formed and cobalt doped Nd2O3 are in progress.
PO-20
Combustion Synthesis of Mn0.3Ni0.3Zn0.4Fe2O4 nano-particles using a novel fumarato-hydrazinate precursor
Umesh B. Gawas and V.M.S.Verenkar*Department of chemistry, Goa University, Taleigao Plateau, Goa-403206, India
Email: [email protected]
Abstract:Carboxylates and carboxylato-hydrazinates of metals are found to be very good
precursors for the synthesis of metal as well as mixed metal oxides, as these precursors decomposes at comparitively lower temperatures yielding ultrafine oxides with high surface area. Here, we are reporting the synthesis of a new precursor manganese nickel zinc ferrous fumarato-hydrazinate, which once ignited undergoes sel-propagating auto-combustion to give nanosize Mn0.3Ni0.3Zn0.4Fe2O4. The precursor has been characterized by IR, chemical analysis, thermal analysis and its chemical composition was fixed. The XRD studies confirmed the single phase formation of nanosized ‘as prepared’ Mn0.3Ni0.3Zn0.4Fe2O4. Infra-red and magnetisation studies were also carried out on the ‘as prepared’ Mn0.3Ni0.3Zn0.4Fe2O4 hints at the nanosize nature of the ferrite particles which was confirmed by TEM. The average particle size was found to be less than 20nm.
Keywords: Mn-Ni-Zn Ferrite, Nano-particles, auto-combustion.
References:
1. D.Gajapathy, K.C.Patil and V.R.Pai Vernekar, Mat. Res. Bull.17 (1982) 29.2. P.Ravindranathan and K.C.Patil, Thermochim. Acta 71 (1983) 53.3. G.V.Mahesh and K.C.Patil, Thermochim. Acta 99(1986)188.4. V.M.S.Verenkar and K.S.Rane, ‘Proc. 10th Nat. Symp. On thermal Analysis’,
Mumbai, India, (1995), 171.5. V.M.S.Verenkar and K.S.Rane, ‘Proc. 10th Nat. Symp. On thermal Analysis’,
Mumbai, India, (1995), 175.6. S.Govindarajan, S.U. Nasrin Banu, N.Saravanan and B.N.Sivasankar, Proc.
Indian Acad. Sci. (Chem. Sci.) 107(1995)559.7. V.M.S.Verenkar and K.S.Rane, ‘Proc. 12th Nat. Symp. On thermal Analysis’,
Gorakhpur, India, (2000), 194.
8. S.Y.Sawant, V.M.Sverenkar and S.C.Mojumdar, J.Therm.Anal.Cal., 90(2007)669.
9. R.A.Porob, S.Z.Khan, S.C.Mojumdar and V.M.S.Verenkar, J.Therm. Anal. Cal., 86(2006)605.
10. A.More, V.M.S.Verenkar and S.C. Mojumdar, J.Therm.Anal.Cal., 94(2008)63.
PO-21
High Temperature electrical and Magnetic studies on Na0.76 Co(1-
X)/Nix/FexO2 prepared aqueous combustion method.
Venkatesan.P1, N.Y.Vasanthacharya2, V.B.Shenoy1, A.M.Umarji1
1Materials Research Centre, Indian, Institute of Science, Bangalore, India-560012.2Solid State and Structural Unit, Institute of Science, Bangalore, India-560012.
Email: [email protected]:
Sodium cobalt oxides are exclusively studied for their electric, magnetic and thermoelectric properties[1].Quantitative evaluation of high temperature material properties have been difficult due to (i) hygroscopic nature of high Na containing compositions and (ii) limitation on sintering temperature due to which bulk density of ceramics is quiet low .Any attempt to sintering results in loss of sodium stoichiometry and non-uniform distribution.
In this work some of this problems are overcome by preparing sinteractive power by aqueous combustion method and compacting them to high density ceramics by hot pressing. Composition of Na0.76 Co(1-X)MxO2 (M=Ni & Fe) with x=0.00 to 0.15 were prepared with metal nitrate and urea redox mixture to produce fine grained combustion products. The powder was subjected to hot pressing in a graphite die under 75MPa uniaxial pressure and heated at 800ok fro 15 minutes using a vacuum induction furnace. The obtained was having density >90-95% theoretical value.
The monophasic composition could be indexed to hexagonal unit cell (P6/mmc space group) with no noticeable variation in the lattice parameters. The four probe electrical resistivity, magnetic susceptibility and thermoelectric power measurement have been carried out in the temperature range 300oK -900ok.The Ni and Fe doped sample showed anomalous at high temperature during heating cycle which was not observable during cooling cycle. The transport and Magnetic properties will be presented.
References:1.Journal of Alloys and compounds-Lie Wang, Ming Wang, Dongliang Zhao .Article in press, May -2008
PO-22
Preparation and Sensor studies on SnO2
Mahesh D.Bedre1, Swaruparani1, Sharnbasava1and A.Venkataraman1*
1Materials Chemistry Laboratory, Department of Materials Science,Gulbarga University, Gulbarga
Email:[email protected]:
Semi conducting tin oxide has been prepared by employing novel solution evaporation method using PEG (Polyethylene Glycol as fuel). The bonding nature of the SnO2 is understood by the FTIR technique. Crystalline nature and the formation are confirmed by confirmed by the XRD and EDAX studies. d.c Conductivity suggest the better semi conducting and gas sensing behaviour when compared with SnO2 prepared by other methods (viz. EtOH, MeOH and H2S).
Key words: solution evaporation method, Tin oxide, H2S, MeOH, EtOH
PO-23
Combustion synthesis, structural characterization and thermoluminescence studies of -rayed Mg2SiO4 nano phosphor
S.C.Prashantha 1,3, B.N. Lakshminarasappa 1*, and B.M. Nagabhushana 2
1Department of Physics, Bangalore University, Bangalore-560056, India2 M.S.Ramaiah Institute of Technology, Bangalore-560054, India
3Vivekananda Institute of Technology, Gudimavu, Bangalore-560074, India E-mail: [email protected]
Astract:
Nano particles have been studied vigorously in recent years because of their significant properties differ from their bulk form and it is expected that they may be considered as potential materials for both fundamental and applications. Nanoparticles of Mg2SiO4, also known as Forsterite is prepared using low temperature solution combustion method from metal nitrate as precursor and oxalydihydrazine (ODH) as fuel. Enstatite free Forsterite has been obtained at temperature as low as 5000C. The effect of temperature on crystalline phase formation has been investigated using PXRD method. The crystallites size are evaluated from Scherer’s formula and it is found to be in the range 40-50nm. The Forsterite phosphor has been characterized by FTIR, SEM and BET surface area. The phosphor shows good porosity and it is found to be mesoporous. The TSL characteristics of rayed Forsterite are studied in detail in the dose range 0.33 to 6.60 KGy at RT. Two prominent and well resolved TL glows with peaks at around 200oC and 300oC besides a shoulder with peak at ~ 330oC are observed. The TSL intensity is found to increase with increase in -ray dose. The TL glow curves are analyzed and the trapping parameters are calculated. TL results on nano Forsterite indicates that this material may be considered as TLD phosphor for high dose -rays.
Indo-Russian Joint Research Program
Department of Science & Technology (DST), Govt. of India and Russian Foundation for Basic Research concluded an MoU for funding of joint research proposals and bilateral workshops in India and Russia in the areas of Basic Science. DST and RFBR invite Indian and Russian scientists / researchers to submit proposals for joint research projects and workshops in the following areas of basic sciences under DST-RFBR cooperation:
- Mathematics, Mechanics and Informatics;- Physics and Astronomy;- Chemistry;- Biology and Medical Sciences;- Earth Sciences;- Telecommunications and Computer Sciences;- Fundamental of Engineering Sciences.
Each bilateral workshop should have two co-organisers, one Indian and one Russian. The total number of participants, with at least half of the participants from the host country.
Support is available for Joint Research in areas of basic sciences only. Joint research projects will be carried out by research teams from both countries. The team leaders must hold a full-time position at a university or research institute in their respective countries. Scientists are advised to submit only one project against this call.
The duration of each project will be two years initially. After the completion of this period, an application for additional one year may be considered on the merit of the progress.
The team leaders should submit an application to respective nodal agency, upon consultations, using the respective forms prescribed by DST and RFBR. Applications submitted by one side only; not on prescribed format and received after due date will not be accepted. Indian/Russian team leaders should, therefore, ensure that their counterpart submits an identical application on prescribed format as per guidelines of nodal agencies by due date.
DST and RFBR will conduct parallel review of the applications respectively based on the agreed criteria. DST and RFBR will make joint decisions based on the review results.
Each project will receive annual funding of up to Rs. 8,00,000 from DST and up to Rbls 5,00,000 from RFBR. This funding will cover the following expenses in connection with a project;
Consumables and other research expenses; Expenditure by project team in their country would be borne by the respective country, i.e., DST would support expenditure on Indian side of the project whereas RFBR would meet the expenditure of Russian side.
Support for Exchange visit component: The sending side would provide return international airfare up to the city of place of work in the host country and cover insurance for emergency illness and accident. The receiving side would arrange in-country travel from the capital city/city of arrival to the place of the visiting institute by appropriate means and provide accommodation and Perdiem in lieu of boarding to the visiting scientists.
Funding will cover the following expenses in connection with organization of a workshop:
International return economy airfare for Indian scientists traveling to Russia to participate in workshop (International travel and associated costs for Russian scientists traveling to India will be met by the RFBR)
Local costs including accommodation and Perdiem in lieu of boarding for Russian scientists traveling to India to participate in workshop (local costs including accommodation and Perdiem in lieu of boarding for Indian scientists traveling to Russia to participate in workshop will be met by the RFBR).
Domestic travel and accommodation for Indian participants of workshop held in India. Organisational expenses (as per recommendation of assessment committee).
Submitting an applicationIndian applicants for funding should submit this completed application form and all relevant, clearly labelled attachments in a single email to the email address: [email protected] For further details and clarifications, if any, kindly contact any of the following in India or Russia:
For India For Russia
Mr. Rajiv Kumar Scientist `C’, International Division Department of Science & Technology, Ministry of Science & Technology, Technology Bhavan, New Mehrauli Road,New Delhi – 110 016., IndiaFax: +91-11-26862418 E-mail: [email protected]: www.dst.gov.in / www.stic-dst.org
International Relations Department,Russian Foundation for Basic ResearchВ-334, FSP-1, Leninsky Prospect- 32AMoscow - 119991, RussiaТеl.: +7– 495- 938-54-58E-mail: [email protected]: http://www.rfbr.ru